Sirona Zi i-Size - More Info

Product Information

  • Length:

    710 mm


    440 mm


    640 mm

  • Weight:

    14 kg

  • Maintenance:

    Fabric covers machine washable at 30°

  • What you get:

    Car seat incl. newborn inlay

  • Engineered and designed in Germany

    Engineered and designed in Germany

  • UN R129/03


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.

Car compatibility

Is this the right seat for my car?

Before buying the child car seat, always check whether it can be properly installed in your vehicle. We recommend a test installation at a qualified retailer. Always follow the recommendations of the vehicle manufacturer regarding the installation of child car seats.

Installation with ISOFIX

Look for the i-Size logo in your vehicle.
If a vehicle seat is marked with this logo, it is suitable for use with all i-Size child car seats and therefore does not feature in our list of compatible vehicles.
If your vehicle does not have an i-Size seat, please check the list to find out whether your vehicle is compatible. If your vehicle is not listed, please contact our Customer Service team.

1. Select car manufacturer

2. Select model and year

If you have any further questions, please contact us

Ask Us


Will the car seat fit in my vehicle?

It is important to check whether the car seat is compatible with your vehicle before you purchase it. The car seat is approved for use in i-Size compatible vehicle seating positions as indicated by vehicle manufacturers in the vehicle users manual. If your vehicle does not have an i-Size seating position, please check the vehicle compatibility list that is included or on our homepage whether the installation is allowed. If your car is not equipped with ISOFIX the use of the car seat is not allowed.

Can I also use this seat in a car without ISOFIX anchorage points?

No, this car seat can only be installed in vehicles with ISOFIX anchorage points, due to the fact that it must be installed with ISOFIX in every position (rear- and forward facing).

The car seat is approved in compliance with the i-Size standard (UN R129). What does this mean?

i-Size is an European standard for car seats. It specifies, among others, that infants must travel in a rear-facing position before the child's age exceeds 15 months and, for the first time, that side-impact protection is tested. To find out more about i-Size go to

What kind of clothing should my child wear when seated in the car seat?

Thick clothing prevents the harness/vehicle belt or impact shield from lying tight against the body. Only a correctly adjusted restraint system can offer maximum protection. For this reason, your child should wear thin, well-fitting clothing. Thick clothing such as winter jackets and clothing with hoods (hoodies, teddy suits, etc.) as well as hats should be avoided. Once your child has been positioned in the seat, he or she can be covered with a blanket for warmth.

Can I use the car seat on lateral facing vehicle seats?

It is not permissible to use the car seat on lateral facing vehicle seats.

Can I use the car seat even when the side airbag is activated?

Yes, the side airbag can remain activated when using the car seat.

What do I have to bear in mind when installing the Sirona in my vehicle?

First select an appropriate vehicle seat. Then fold out the load leg. This has to lock with an audible CLICK. The car seat is installed using the vehicle’s ISOFIX anchorage points. Press the release buttons of the ISOFIX connectors and push it out of the base to their furthest extend. Then push the ISOFIX connectors into the ISOFIX anchorage points. Make sure it is locked with an audible CLICK and that the safety indicators show green. Next, push the base towards the backrest of the vehicle seat until it is fully aligned with the backrest. Moving the whole car seat from side to side will further brace it with the backrest. Make always sure that the load leg is folded out completely. Push the adjustment button on the load leg upwards and press it to pull the load leg out. After this, pull the load leg out to the next locking position. Make sure, the load leg indicator on the base shows green.

How should the headrest be adjusted?

Only a headrest adjusted to the optimum height will give your child the best possible protection and comfort. The height can be adjusted in various positions. The headrest must be adjusted so no more than 2-3 cm fit between the child’s shoulders and the bottom of the headrest.

Do both side-impact protectors (L.S.P.s) have to be installed?

The Linear Side-impact Protection (L.S.P.) reduces the forces of a side-impact collision and thus also the risk of injury. Generally, we advise parents to install the L.S.P. on both sides of the car seat. If, however, there is insufficient space to install the L.S.P. nearest the middle of the vehicle, it is not absolutely essential. If the car seat is installed on the front passenger seat, or if a passenger is sitting beside the car seat in the rear of the vehicle, ensure that the L.S.P. element facing the inside of the car is folded away. For safety reasons, please ensure that the L.S.P. nearest the door is always installed.

When am I allowed to use the forward-facing position of the Sirona?

Once the child exceeds 15 months of age and has reached a minimum size of 76 cm you are allowed to use the forward-facing position of your Sirona car seat. This is not a must. We rather recommend to transport children in the rear-facing position of Sirona as long as possible, the car seat allows it up to a size of 105 cm, approx. 4 years.

Why can’t I rotate the seat by a full 360°?

The Sirona features Driving Direction Control which prevents the car seat from being rotated a full 360˚ until the child's age exceeds 15 months and reached a size of 76 cm. This is to ensure that the child travels in a rear-facing position before reaching the minimum age and a minimum size, as mandated by the i-Size regulation. During the child's first 15 months the rotation mechanism makes it easy to switch from the rear-facing position to the door-facing boarding position. Once the child has reached the minimum age and height you will be able to unlock the Driving Direction Control by moving a switch on the backrest to a point indicating the age and size of your child. This makes it possible to rotate the seat to the forward-facing position without having to remove and reinstall the seat, which can be an awkward task that can cause back strain. It is not a must to adjust the seat to a forward-facing position at this point, and in fact we recommend transporting children in the Sirona's rear-facing position for as long as possible.

How can I switch the car seat from a rear-facing to forward facing position?

When the child exceeds 15 months of age and has reached a minimum size of 76 cm you are allowed to use the forward-facing position of your Sirona car seat. This is not a must. We rather recommend to transport children in the Sirona in the rear-facing position as long as possible. An indicator on the headrest of the car seat shows the height of the child, from which the car seat can be changed to the forward-facing use at the earliest. In the beginning the car seat is blocked for forward facing use. To switch the car seat in a forward facing position move the headrest cover up and the backrest cover down and move the switch on the backrest to the age and size of your child. Then pull the position adjustment handle and while keeping the handle pulled, bring the seat shell into a completely upright position and rotate the seat shell forward-facing.

When should I remove the newborn inlay?

The newborn inlay should be removed when your infant reaches a height of around 61cm (corresponding to approximately 3 months). This ensures that your growing baby has enough space in the car seat.

Can I use this car seat on a flight?

No, this car seat is not approved for use on an airplane.

Is my child allowed to rest his/her legs on the rebound bar?

Relatively tall infants may rest their legs on the rebound bar. Bending the legs at the knee does not affect safety in any way. As long as the child has sufficient legroom you can use the seat in a rear-facing position.

When is a child too big for the rear-facing car seat?

The rear-facing car seat can be used by infants from 45 cm to a maximum height of 105 cm or a maximum body weight of 18 kg (approx. 4 years).

How do I install the cup holder?

On either side of the car seat there is a little opening in the fabric of the seat cover indicated by stitching. If you look inside this opening you will see a grooved area in the car seat shell which the cup holder can be slotted into.

Can I wash the newborn inlay and cover of the car seat in the washing machine?

Yes, both are washable. Note however, that the foam in the newborn inlay needs to be removed before washing via dedicated slots. You can put the foam back through the slots after the newborn inlay is washed and dried. We recommend using a delicate wash cycle and a maximum temperature of 30 degrees. Detailed instructions can be also found in the user guide.

Is it ok to keep using a car seat after an accident?

We at CYBEX strongly recommend that you replace a car seat after any kind of accident. This is because tiny hairline cracks, which may not be visible to the naked eye, can appear in the plastic parts of a car seat after an accident. These cracks can pose an increased risk to safety.

My car seat is faulty, how can I get it repaired?

Please refer to the retailer where you bought your CYBEX car seat. They will deal with the matter on your behalf.

Where can I get replacement parts for my product?

You can order replacement parts from a specialist retailer near you. To find a store near you, simply go to the store locator on our website:

How do I know when my child needs to change to the next car seat?

We generally advise against switching to the next car seat prematurely. Even if your child’s feet protrude outside the car seat, your child has not necessarily grown out of the car seat. However, if your child's head is protruding above the top edge of the highest headrest position and your child weighs over 18 kg, it is time to change the car seat, as it no longer affords sufficient protection to the vulnerable neck and head area. After changing the car seat, your child’s head should be positioned within the protective area of the height-adjustable headrest and, if existing, enabling your child to see comfortably over the impact shield. If your child disappears behind the impact shield, then he/she is definitely too small for the seat.