Depending on the size of the child, convertible car seats can be either rear facing or forward facing children. Tiny babies should be rear facing but as the child grows, the seat can be forward facing. The straps are adjustable so that they are always centered between the shoulder and the neck. When a convertible car seat is rear facing, it should be attached to the LATCH system in the car's seat back. The unused lower connectors can be secured on many of the convertible car seats so that they don't fly around in case of an accident.
When a convertible seat is turned to be forward facing, there is a mandatory tether strap that must be hooked into cars that have were manufactured after 2001. Cars older than that can be retrofitted.