Most safety seats fit better into some vehicles than others. Cars with bucket seats or small rear seats may present problems. Strap on metal slide adjustor must be threaded back throguh the slide to hold tight. There are three kinds. The basic 5-point harness has shoulder, hip, and crotch straps.
Most seats come with a plastic harness retainer clip that holds the two shoulder straps together.
Keep it at armpit level on your child to hold the harness straps on the shoulders. This kind of harness can be adjusted to fit snugly on both very small infants and larger children. However, the straps may twist and tangle. Keep the straps flat for maximum protection. The shield reduces twisting of shoulder straps.