Sirona S - More Info

Product Information

  • Length:

    30 in


    19 in


    24 in

  • Weight:

    30.4 lbs

  • Maintenance:

    Machine washable COLD, delicate cycle, mild detergent. Hang dry. For more information, see user manual.

  • Engineered and designed in Germany

    Engineered and designed in Germany

The pictures of products and the measurements on this website are for indication purpose only. Products may vary and we reserve the right to make product changes.


Will this car seat fit my child?

The Sirona S is designed for children between 4-65 lbs. (1.8-29.5 kg) with a height between 17”-49” (43.1-124.4 cm). Children weighing more than 65 lbs or more than 49” should consider a booster seat that accommodates their weight, height and age.

Will the Sirona S fit my vehicle?

The Sirona S has been fit tested in a variety of vehicles. Due to variations in make, models, and years of manufactured vehicles, however, you are encouraged to try the seat in your vehicle at a retail location nearest you. You should try both rear facing and forward facing modes and in different locations (outboard rear seat, vs middle seat).

Where can I check to make sure my car seat is installed properly?

Cybex recommends getting your seat installation checked by a Certified Child Passenger Safety Technician. You can find this free service by visiting to find a seat check nearest you.

Does the Sirona S have an expiration?

You can find the date of manufacture and expiration date on a sticker located on the bottom of your Sirona S. Every car seat has an expiration due largely to allow you the benefit of regulatory changes and technology enhancements in child passenger safety. The Sirona S has been certified for 10 years from the date of manufacture. Once your car seat has reached its expiration date, we recommend recycling the seat by contacting your local community recycling center

How much does the Sirona S weigh?

The weight of the car seat (excluding the infant positioning pillow is 30.4 lbs. (13.8 kg.)

How big is the Sirona S?

The range of dimensions of the Sirona S are as follows:
i. Rear-Facing upright position: 23”H x 21.5” W x 30” D
ii. Forward-Facing upright position: 31”H x 19”W x 28.5”D

What fashions are available for the Sirona S?

The Sirona S is available in Black, Premium Black, Manhattan Grey, and Indigo Blue.

Where is the Sirona S available for purchase?

You can find the nearest retailer on our website at

Where do I store/find my Lower Connectors on my Sirona S?

Storage for Lower Connectors can be found in slots on either side of base. When Storing Lower Connectors, slide each Connector back into its storage slot until an audible click is heard. EasyLock™ Bar and Belt Tensioner must also be closed. Remove most of the slack from the lower anchor strap by pulling on the lower anchor Adjuster Strap until it lays flat through the Belt Guides. Tuck the excess strap into the vehicle seat crease to get it out of the way.

Is it safer to use lower anchors or the vehicle’s seat belt?

The safest installation method is the one that allows you to install the car seat correctly. Either method, if used in accordance with the child safety seat manual and vehicle’s owner’s manual requirements, provides protection and the seat has been tested to meet safety standards installed by both methods.

Which installation method is recommended?

The seat can be installed with either lower anchors or the vehicle seatbelt. Because of the weight restrictions of the lower anchors, and the unique installation method of Sirona S, the vehicle seatbelt will support the weight of the child from 4-65 lbs. (1.8-29.5 kg) and not require the parent to reinstall the seat.

Can I install the Sirona S using both lower anchors AND the vehicle seat belt?

No. You can use only either the vehicle seat belt or lower anchors-not both. The Sirona S should be installed using only one installation method.

How do I know if I have LATCH available in my vehicle to install the car seat?

Most U.S. vehicles manufactured on or after September 1, 2002, are equipped with LATCH. Refer to your vehicle owner’s manual under the Child Restraints section to confirm.

Do I have to use the vehicle seat belt installation method?

The Sirona S allows for the use of lower anchors up to 30 lbs (13.6kg) for rear-facing mode and 35 lbs (15.9 kg) in forward-facing mode. However, the vehicle may have additional limitations (Refer to your vehicle owner’s manual typically under Child Restraint or Child Safety in the index). When you can no longer use lower anchors, the Sirona S must be installed using the vehicle’s seat belt. For forward-facing installations, use the tether whenever possible.

Can I use the lower anchors in the rear center seat?

You should refer to the vehicle owner’s manual for the center seat lower anchor installation. CYBEX allows lower anchor installations of Sirona S in the center seating position if the width of the lower anchor bars in the vehicle is between 11-20” and the vehicle manufacturer also allows. If the vehicle owner’s manual does not specify, or is not clear, it is recommended to contact the vehicle manufacturer for clarity.

Do I need to use the top tether for forward-facing installation?

The Sirona S convertible car seat includes a tether for forward-facing use and typically, CYBEX recommends the use of tether when installing a car seat in a forward-facing position. The Sirona S innovative load leg feature, however, like a tether, is designed to reduce seat movement in the event of a crash, so use of the tether is not required in forward-facing mode for this seat when using load leg. Importantly, the Sirona S meets or exceeds applicable U.S. federal safety standards both with and without the tether, and with and without the load leg.

Why is it important to use the tether for forward facing installation?

The use of a tether can reduce the risk of injury by reducing movement of the car seat and the child in certain kinds of crashes. The tether should be used whenever possible for forward-facing installations with either the lower anchors or seat belt. For proper installation, please refer to both the child safety seat manual as well as the vehicle’s owner manual.

I cannot find the anchors on my vehicle for LATCH. How can I find them?

In some cases, the lower anchors may be recessed within the vehicles seat bite. The tether anchor is often behind the rear seat head rests. If your vehicle was manufactured after September 1, 2002, the vehicle should be equipped for LATCH. In most cases, there will be icons near the locations of the anchors. However, it is best to refer to the vehicle’s owner manual to help identify the locations.

How do I uninstall the lower anchor connector from my vehicle anchor bars?

To remove the seat from the vehicle when using lower anchors, it is best to loosen the webbing first. Pull up on the lower anchor adjuster to release the tension in the belt. Once the tension has been released, you simply pull the red loops for the lower connectors.

How do I uninstall the tether anchor connector from my vehicle anchor bar?

Push the flat metal end of the tether to unhook it from the seat.

If car seats are required by government regulation to be flame-retardant, how does CYBEX make sure it meets the government standard?

Flammability testing of car seats is required under the FMVSS 302, Flammability of Interior Materials Standard. The test measures the rate of flame spread with the goal of maximizing the amount of time a caregiver would have to remove an occupant from the car seat in the event of a vehicle fire. CYBEX car seats are tested by an accredited independent testing laboratory and meet the FMVSS 302 standard.

Where do I route the vehicle’s seat belt in the Sirona S?

The seat routing for the Sirona S can be found below the belt path cover located on the anti-rebound device. In order to see the belt routing path, move the seat to the most upright position and rotate the seat to face the rear of the vehicle and use the two openings in the belt path cover to pull open.

How do I use the belt tensioner on my Sirona S?

For detailed instructions on how to use the belt tensioner on the Sirona S, please refer to page 55 of the instruction manual. You can also reference the Sirona S installation videos by scanning the QR code located on the Belt Path Cover on the base.

How long do I use the newborn insert?

The newborn inserts should only be used in rear-facing mode to ensure a better fit for smaller infants. Once the child has outgrown the need for the newborn inserts, the inserts should be removed and stored.

Do I have to use the infant insert?

The purpose of the newborn inserts is to ensure a snug fit when harnessing your child and should only be used to ensure a better fit for smaller infants.

How do I know my child is properly positioned in the Sirona S?

Place the child in the car seat with their back and bottom flush with the seating surface.
Adjust the headrest so that the shoulder straps are positioned at or below the child’s shoulders for rear facing, and at or slightly above in forward facing mode.
Next, conduct a pinch test to determine a snug harness fit: the middle finger along with the thumb and forefinger pinch the strap where it comes over the shoulder. Place your middle finger under the harness webbing to pull it up slightly, then use the other two fingers to pinch. If there is no excess webbing, the harness is snug. If you can find excess webbing that can be easily folded, then the harness is too loose.

When should I move my child from rear facing to forward facing?

The American Academy of Pediatrics recommends children stay rear-facing until they outgrow the maximum weight or height of their car seat for rear facing. The Sirona S can accommodate a child in rear-facing mode until 50 lbs, 49 inches or their head is less than an inch from the top of the headrest.

How do I rotate the Sirona S?

The Sirona S rotates in its base, making it easy to safely load and unload your child when the seat is properly installed. To rotate the seat, squeeze the Recline Handle and move the seat past the most upright position. The Rotation Lock Indicator will display an “Unlock” image. Rotate the seat to your desired loading/unloading position. When your child is securely harnessed, rotate back to Rear-Facing or Forward-Facing position based on your child’s size. Then, move back into a locked recline position. The Rotation Lock Indicator will display a “Lock” image.

What is a Load Leg?

The load leg stabilizes the car seat and can help reduce crash forces.

When should the Load Leg be used?

The Load Leg should only be used if all installation requirements are met. Refer to the child seat manual for detailed instructions.

What is the L.S.P System?

The L.S.P System (Linear Side-Impact Protection) allows the forces from a near side impact collision to be reduced gradually to help minimize injuries. This system has been optimized to protect and reduce forces on your child in the event of certain side impact crashes.

When should the L.S.P System be used?

It should only be used when the car seat is installed in an outboard seating position. Extend the LSP on the side of the car seat that is closest to the door.

Where is the Sirona S manual located?

On the back of the seat is a snap door where the Sirona S manual can be found. To gain access to the manual, simply open the door and remove the manual. Before installing the child safety seat, always refer to the child seat manual as well as the vehicle’s owner manuals for important instructions regarding proper installation. It is always recommended to keep the car seat manual with the car seat for easy reference.

If I lost my manual, where can I get a new one?

Manuals can be found online at Simply click at the top right to select the category and model. The free manual download is located at the bottom of every product page or call customer service with your model number.

Do I have to register my seat?

NHTSA recommends all users register their car seats to receive important updates or recall notifications. This information cannot be used for marketing purposes. You can register your Sirona S in one of three ways: using the postage-paid postcard attached to the car seat at purchase, entering the information online at or via the SensorSafe application.

Can I use the Sirona S on aircraft flights?

This restraint is not certified for aircraft use.

How do I know if the Sirona S is installed at the correct recline?

The Sirona S is equipped with 2 recline level indicators to assist with installation recline (one in Spanish and one in English). To ensure the best results, it is important that the base of the seat is completely flat against the vehicle seat prior to using the recline indicators. To use the indicators for recline, look for the silver ball in the clear windows. When in rear-facing mode, the metal ball should be in the blue areas of the indicator. When forward-facing, the metal ball should be in the red areas of the indicator.

How do I know if the seat is properly secured?

To check the installation, hold the car seat at both sides at the belt path and pull side to side and forward. The car seat should not move more than 1 inch (2.5cm) from the vehicle seat back or side-to-side. If it moves more than 1 inch, try tightening the vehicle seat belt or lower anchors. Also, make sure you are using the tether anchor for forward- facing car seat installations.

What do I do if I have a hard time getting the belt tensioner to close?

If you have a hard time closing the belt tensioner, first ensure that the seatbelt is properly routed through the belt guides and there are no extra folds. Check to make sure the lower anchors are not interfering with the belt tensioner, and double check that you haven’t over tightened the seatbelt before trying to secure the belt tensioner. For additional help contact customer service.

Does the Sirona S need to be replaced after a crash? What if the car seat was unoccupied at the time?

Yes, if the car seat is involved in a crash it must be replaced, even if the car seat is unoccupied at the time of the crash.

What should I do if the load leg of my CYBEX Sirona S is touching the floor, but the lower indicator is still showing red?

The CYBEX Sirona S has two proper use indicators on the load leg. Both must show green while the car seat is occupied by a child for travel. The indicator at the top informs you if the load leg is locked in the correct position. The indicator at the bottom informs you if the load leg is in contact with the vehicle floor. The load leg must be in a locked position and in contact with the vehicle floor. Sometimes, the load leg may be in the correct position and in contact with the vehicle floor, but the indicator is still red. Do not attempt to over-extend the load leg to force the lower indicator to turn green. Over extending the load leg may cause the base of the car seat to raise off the vehicle seating surface. There may be times when the load leg is properly installed and you have not yet placed your child in the seat when one of the indicators is showing red. If that happens, place your child in the car seat, or use your hand to apply light downward pressure, to determine if that additional weight help the indicator turn from red to green. Both indicators must be green when the car seat is occupied by a child for travel. However, the bottom indicator may go back to red when the seat is unoccupied.

What can I do to stop the CYBEX Sirona S from sliding down out of the rotation position during the installation?

The CYBEX Sirona S features an unlocked, fully upright position to allow the car seat to rotate 360 degrees. This position does not lock in place by design to help ensure that the seat locks into a rear-facing locked position for use of the seat with your child. The Sirona S must be facing the rear of the vehicle in this unlocked position in order to access the belt path used for installation with either the vehicle seat belt or lower anchor system. If you turn the car seat slightly to the right or left, while in the rear-facing upright position, you should be able to prevent it from sliding down into a locked rear facing position during your installation. Be sure to turn the seat back into position after you complete your installation to ensure it locks properly before use.

Why should I download the SensorSafe mobile app for use with the Sirona S?

Originally developed to prevent the rising number of infant hot car deaths, SensorSafe goes a step further to monitor the wellbeing of the child while the vehicle is in motion through the smart chest clip that is synced with the installed vehicle receiver and the caregiver's smartphone.

Will SensorSafe still alert me that my child is in the car if I’m not connected to Bluetooth?

In order to take full advantage of the SensorSafe features, a mobile phone with Bluetooth is required. However, basic reminders can still be communicated to the caregiver through the vehicle receiver. The vehicle receiver will emit a chime which alerts the caregiver when:
i. A child unbuckles the chest clip while the vehicle is in motion.
ii. The vehicle is turned off if there is a child buckled in a car seat.

Do I need to have Bluetooth in my vehicle to use SensorSafe Technology in the car seat or the app?

The vehicle does not need to be equipped with Bluetooth for SensorSafe to work. The technology is set up to work between the SensorSafe chest clip, the SensorSafe vehicle receiver, and the caregiver’s smart phone.

How do I add family members to the app for emergency notifications?

When the application is open, click on the setting icon. Under the section titled “Family Members”, select the link to “Invite Members”. When you click on the link, you will be asked to provide the first and last name, relationship and email of the member you wish to add. Click “Send invite” to complete your part of the setup.
Once you have sent the invite, the invited member should receive an email with a unique code to use to join your family. They will need to download and register the application under their name to join. Once they have completed the application setup, they will need to open their version of the application, click on the settings icon at the bottom, and under the “Family members” section click on the link titled “Join Family.” They will be prompted to use their unique ID to join your family.
Only invited members can join your family.

When will family members be notified in an emergency?

If a caregiver is running the SensorSafe mobile app with a buckled child in the vehicle, and leaves the vehicle, the phone will lose the Bluetooth connection to the SensorSafe system, which triggers warning messages in the app. Once the Bluetooth connection has been lost, the caregiver has two minutes to address the issue by removing the child from the vehicle or dismissing the alarm. If no action is taken, the family members that have been set up in the caregivers application will be sent a notification which includes the last known location of the vehicle.

Will first responders be notified in an emergency?

No. The only individuals notified in an emergency are those listed as “family members” in the caregiver’s profile in the app.

How do I know if the SensorSafe Technology is working?

SensorSafe Technology will always provide a reminder tone when the vehicle ignition is turned off if a child is buckled in a SensorSafe equipped car seat. If you do not hear this alarm, uninstall and reinstall the receiver plug in the vehicle.
If you are the mobile app account user in the vehicle, you can also use the SensorSafe app to view the status of the SensorSafe chest clip. When a child is buckled in the vehicle, the app will indicate when the vehicle is in motion or stopped and will read the air temperature around where the child is seated.
If you have a question about the operation of the Technology, please contact our customer service team: 1-877-242-5676.

Can I use the SensorSafe system in ANY vehicle?

The SensorSafe receiver works ONLY with 2008 or newer gas, diesel, hybrid or start/stop vehicles purchased in the US or Canada. You must configure your receiver based on the type of engine in your vehicle.

Can I move my SensorSafe receiver between vehicles?

No, the SensorSafe dongle is designed to be installed in only one vehicle and should not be moved after installation. Unplugging and re-plugging the
receiver repeatedly risks damage to the connector pins which are essential for its function.
You can also purchase a second receiver plug if you plan to move the car seat regularly between two different vehicles. Contact our customer service
team for more information: 1-877-242-5676.

Is the SensorSafe chest clip transmitter safe for use near my child?

The SensorSafe chest clip transmitter is certified safe for use by the US Federal Communication Commission and IC Canada. It transmits an extremely brief, very low power signal no stronger than your car’s keyless remote entry. The transmissions are so brief that total transmission time in two hours of driving is less than one second. Please be aware that this product does contain magnets. Before use, consult your family doctor about the compatibility of this product with pacemakers and similar devices.

Will the SensorSafe system interfere with my vehicle’s operation, keyless entry or make the garage door go up and down?

The SensorSafe receiver plug will not interfere in the operation of your vehicle or other devices. The receiver plug uses the connector port for power to monitor the SensorSafe chest clip and to determine if the car is ON or OFF.