The Safe-N-Sound Hi-Liner SG Booster Seat is a popular choice among parents looking for a seat to suit there 4 + year old child. Suitable for children approx. 4 years to 6 - 8 years of age. It has a width of approx 420cm which makes it a great choice when you require three seats for your growing family. Your child can use the Hi-Liner SG once their shoulders are in line with the Lower Shoulder Height Marker with the headrest in the lowest position. If below the Lower Shoulder Height Marker your child is too small for the Hi-Liner SG and should remain in a restraint with an in-built harness. Your child can continue to use the Hi-Liner SG until their shoulders reach the Upper Shoulder Height Marker with the headrest fully raised. When your child reaches this stage they are most likely to be of an age that no longer requires a car seat restraint. Expandable Booster Seat - Hi-Liner SG is the first Expandable Booster Seat designed with slots in the seat cover and shell. This makes it compatible with Safe-n-Sound Protecta PLUS Harness for added safety. The Hi-Liner features the exclusive Safe-n-Sound SLIGEGUARD Clip. The SLIDEGUARD Clip is a life saving device that prevents your child from sliding under the lap-belt (submarining) during impact, thus minimising the risk of abdominal injury. Deep side wings are EPS foam lined providing additional protection in a side impact crash.