A car's seatbelt, whether front or rear, consists of several components. These include the fabric belt that supports the passenger, the retractor box housing the spool and spring, the fastening buckle, and the metal latch. Generally, there are two types of seatbelts: the pretensioner and the retractable types.
In a pretensioner seatbelt, the mechanism relies on sensors installed throughout the device. These sensors measure speed and impact intensity to provide appropriate tension to restrain the passenger. In a collision, this type of seatbelt might cause fractures, burns, or neck pain.
The retractable seatbelt operates on a mechanical spring system. In the event of a collision or a rollover, it automatically locks to protect the passenger.