The Hi-Liner is a tall, moulded plastic booster with an adjustable head rest, and is attached to the vehicle by an upper tether strap. The Hi-Liner does an excellent job of guiding the seatbelt into the correct position. The high side-wings can be adjusted upwards as the child grows, to ensure maximum side impact protection. It features a slide guard clip, which helps prevent a child from sliding off the seat and guides the lap part of the belt across the hips. If the seat is used in a position that only has a lap seatbelt, then an approved child safety harness must be used. It’s important to check your booster seat is compatible with a harness. As children grow and develop, their height and weight changes considerably. For many 4 year olds, a forward-facing safety seat will still be the right size restraint for them. A booster seat should only be used once the child has outgrown their safety seat by reaching the maximum height for the seat. A booster is a restraint designed to elevate a child so they can wear a seatbelt correctly while providing side protection from both the vehicle and other passengers. Children travelling in a booster seat should continue using it until they’ve outgrown it, and once they have and can’t fit the adult seatbelt correctly, then you'll need to use a larger booster seat. This page also provides installations videos and fact sheets. A correctly fitted restraint is critical in keeping your child safe when travelling in your car. That’s why RAA offers expert advice on child restraints and a range of restraint checks and fitting services. RAA Members get a free fitting with every restraint purchased from RAA within the last 12 months. * For more details, contact the Safety Centre on 8202 4592. *Terms & conditions apply