Group 2/3 Car Seat | High Back Boosters Our range of Car seats & highback boosters for children provides the safest option for those leaving and moving on from Group 1.  As your child grows the high back booster provides a combination of height-adjustable backrests and head and shoulder protection, keeping them safe, secure and comfortable, while also helping to make them feel more grown-up. To find out more about High Back Boosters please read here: RSPA Car Seat - High Back Boosters