Sirona S i-Size

360° convenience for you – optimised safety for your child


UN R129/02



45 cm - 105 cm


Max. 18 kg


From birth up to approx. 4 years

Compatible with

Sirona S i-Size with SensorSafe Get More Info
Sirona S i-Size Granite Black Sirona S i-Size Navy Blue Sirona S i-Size Magnolia Pink Sirona S i-Size Soho Grey Sirona S i-Size Deep Black Sirona S i-Size Autumn Gold Sirona S i-Size River Blue Sirona S i-Size Classic Beige Sirona S i-Size Victory Black Sirona S i-Size Racing Red

Sirona S i-Size - Video

CYBEX Sirona S i-Size Tutorial

Sirona S i-Size - More Info

Product Information

  • Length:

    700 mm


    430 mm


    635 mm

  • Weight:

    15 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 R129/02


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


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

We at CYBEX strongly recommend that you replace a 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 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 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:

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

Thick clothing prevents the harness from lying snugly against the body. This incorrect belt positioning could result in the harness slipping off the shoulder. For this reason, your child should wear everyday clothing. Thick clothing such as winter jackets should be avoided where possible. Once your child has been positioned in the seat, he/she can be covered with an extra blanket for warmth.

Can I use this seat on a flight?

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

Why only rearward-facing until 15 months and not for 4 years in total?

The head of a young child is large and heavy in proportion to the rest of their body and their neck is relatively weak. A rear-facing child restraint supports the head and neck and is thought, therefore, to reduce the risk of neck injury. Although this remains a topic for research, European regulators are satisfied that by 15 months, the neck has developed enough strength to withstand the forces in a typical crash. For this reason, 15 months was set as the minimum age for rear-facing. However, many R129 child restraints are approved for longer rear-facing use, for example, by children up to 105 cm (around 4 years).

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 we recommend using the seat in a rear-facing position, which exposes the child to less force in the event of a collision.

Do both LSPs have to be extended for safety reasons?

To provide the best possible protection, the telescopic L.S.P. protector nearest the door should be extended as far as possible. It is designed with two settings. If in the longest setting, the L.S.P. touches the vehicle door, then the first setting must be used instead. When the seat is installed in the middle seat, the linear side-impact protection (L.S.P. System) should not be pulled out.

Can I use the seat and the base when the side airbag is activated?

Yes, side airbags may remain activated when using the baby seat.

From what age and size can the Sirona S i-Size be used?

The Sirona S i-Size can be used for newborns and children from 45cm up to a height of 105 cm (maximum body weight: 18 kg). This roughly corresponds to an age of four years.

What is the weight limit for using the Sirona S i-Size?

The Sirona S i-Size can be used for children up to a maximum body weight of 18 kg.

The Sirona S i-Size is approved in compliance with the i-Size standard (ECE R-129). What does this mean?

i-Size is a new European standard for car seats. It specifies, among others, that car seats have to be installed with ISOFIX, that infants must travel in a rearward facing position up to the age of 15 months and, for the first time, that side-impact protection is tested.

Will the Sirona S i-Size fit in my vehicle?

It is important to check whether the Sirona i-Size is compatible with your vehicle before you purchase it. This is because the Sirona S i-Size is solely an ISOFIX seat and can only be installed in i-Size certified vehicles or in vehicles with ISOFIX anchorage points. Before purchasing the seat, please refer to the compatibility list on the CYBEX website to see whether the Sirona S i-Size is compatible with your vehicle or not.

Can I also use the Sirona S i-Size in a car without i-Size certification?

The Sirona S i-Size can also be used in cars without i-Size certification. However, it is important to emphasize that the vehicle must be fitted with ISOFIX anchorage points. Before purchasing the seat, please refer to the compatibility list on the CYBEX website to see whether the Sirona S i-Size is compatible with your vehicle or not.

What aspects should I bear in mind when installing the Sirona S i-Size in my vehicle?

The Sirona S i-Size is installed using the vehicle’s ISOFIX anchorage points. The one-click installation with the ISOFIX system is a simple way to install the seat in both, forward and rear-facing position and enhances safety. The integrated support leg ensures additional stability and absorbs the forces in case of an impact. A green indicator confirms the correct installation.

Can I also use the Sirona S i-Size in a car without ISOFIX anchorage points?

The Sirona S i-Size is solely an ISOFIX seat and can only be installed in vehicles with ISOFIX anchorage points or in i-Size certified vehicles. Please refer to the compatibility list on the CYBEX website to see whether the Sirona S i-Size is compatible with your vehicle or not.

How can I switch the Sirona S i-Size into a forward-facing position?

We would like to draw your attention to the fact that the Sirona S i-Size should be used in a rear-facing position for as long as possible for maximum safety. However, the seat can optionally be switched to forward-facing. To do so, the seat can be rotated the forward-facing position once the child has reached a min. height of 76 cm and is 16 months old.

How do I secure my child in the seat properly?

In a Sirona S i-Size your child is secured with a five-point harness. The harness should be strapped tightly so that there is space for one hand between the harness and the body of the child. In a forward-facing position, this harness system is fitted with an Energy Reduction Technology, reducing the forces on the neck of a child during a front crash by approximately 20%, compared to other existing harness systems.