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Child seats with the R129/i-Size standard

The safety of children in road traffic is a top priority. Child restraint systems, better known as child seats, are essential for this. The R129 standard, also known as i-Size, is the current European regulation that specifies a high level of safety for child seats. This guide will tell you everything you need to know about child seats that comply with the R129/i-Size standard.

What is R129/i-Size?

R129 or i-Size is an EU safety standard that has been in force since 2013 and is gradually replacing the older ECE R44 regulation. It sets stricter safety standards, including mandatory side and frontal impact protection tests, the use of Isofix attachment systems (instead of car seat belts) and the introduction of size classifications instead of weight classes.

Advantages of i-Size child seats

  • Improved side impact protection: i-Size seats must undergo stringent side collision tests.
  • Size-based selection: Based on the child's height rather than weight, the aim is to ensure longer and therefore safer use of the child seat in the rear-facing position.
  • Isofix attachment: The error rate when installing the seat should be reduced thanks to the simple and standardized attachment.
  • Rear-facing travel: Children up to 15 months must be transported rearward-facing in i-Size seats, which increases safety.

Priority criteria for selection

1. Height and weight of the child

i-Size child seats are classified according to the size of the child and not the weight. The seats can usually be used from birth up to a defined maximum height.

2. correct installation

The Isofix attachment system is designed to enable simple and safe installation. Check whether your car is suitable for Isofix child seats by consulting your car manual or the child seat manufacturer's vehicle type list.

3. type of child seat

There are different types of child seats:

  • Infant carriers: For infants up to approx. 75 cm (depending on manufacturer).
  • Reboarder: Rear-facing child seats that can be used up to the age of four or more.
  • Combi seats: Can be converted from rear-facing to forward-facing use.
  • Booster seats: For taller children who have almost reached the minimum height for using the normal seat belt in the car.

4. comfort for your child

Breathable materials, sufficient space for the child's growth and a comfortable seat are important to make the journey as comfortable as possible for the child.

5. ease of use

The seat should be easy to adjust and clean. It should also be easy to switch between different vehicles if necessary.

6. Additional functions

Some i-Size seats offer additional features such as adjustable reclining positions, integrated sun canopies or additional side impact protection.

Installation and instructions for use

  1. Isofix base: Make sure that the child seat is firmly attached to the Isofix base.
  1. Instructions: Follow the manufacturer's instructions when installing the child seat.
  1. Correct fit: Check that the seat does not wobble and remains firmly in place.
  1. Check: Check regularly that the seat is still appropriate for your child's size.

Care and maintenance

  • Wash the covers according to the manufacturer's instructions.
  • Check the seat regularly for damage or signs of wear.
  • Replace the child seat after an accident, even if there is no visible damage.

When a new i-Size seat is necessary

It is time for a new model if:

  • Your child has reached the maximum size or age for the current seat.
  • The seat is damaged or has been involved in an accident.
  • The seat no longer meets current safety standards.


Child seats that comply with the R129/i-Size standard offer a high level of safety for your children on the road. When making your choice, make sure it is an exact fit for your child's height and weight, check compatibility with your vehicle and make sure it is installed correctly. Remember that the safety of the child seat must be constantly checked and updated if necessary.