A properly-fitted 5-point harness gives the best possible protection for your child.
A 5-point harness has straps that go over both shoulders and both hips and then buckles at the base. The car seat label will tell you the weight and height range of the harness. Check regularly to make sure your child hasn’t outgrown it.
A seat belt is also a type of harness and is used on older children in booster seats. Every passenger in a moving vehicle must use some form of harness for protection in case of a crash.
Click this link for further information: https://ucsg.safekids.org/basic-tips/right-fit/#1