An i-Size car seat meets the requirements of the R129 regulation that was passed in 2013. The most important difference compared to the ECE R44/04 regulations is that i-Size car seats are divided into groups based on the length of the child instead of their weight. Another difference is that i-Size car seats have successfully completed a side impact test. I-Size car seats come in different versions. For example, a Maxi-Cosi with i-Size for babies or a Babyauto car seat that you can transport your preschooler of 15 months backwards in. All i-Size seats have isofix attachment. In the manual of your car, you can check if a i-Size child safety seat fits in your back seat.