i-Size safety for growing children ADVANSAFIX M i-SIZE is designed to protect children from 15 months, right up to the age of 12 years. Approved to the new i-Size regulation, it offers safety you can trust, and maximum flexibility. The seat converts from a harnessed seat to a highback booster seat, with just a few simple steps. Children can benefit from 5-point harness protection up until they reach 21 kg. i-Size safety for all ages The ADVANSAFIX M i-SIZE will protect your child from their toddler years all the way to when they no longer need a child car seat - giving them the ideal car seat safety in one combination seat that is approved to the new i-Size regulation. What's more, its 5-point harness can be used for longer as it's suitable for children up to 21 kg. Flexibility at your fingertips Thanks to the FLIP&GROW function, you can easily change from the integrated 5-point harness to the car?s 3-point seat belt as your child moves to the next stage. And because no parts have to b