The purpose of locking retractors is to provide the seated occupant the convenience of some free movement of the upper torso within the compartment while providing a method of limiting this movement in the event of a crash. Starting in 1996, all passenger vehicle seatbelts must lock pre-crash meaning they have a locking mechanism in the retractor or in the latchplate. Seat belts are stowed on spring-loaded reels called "retractors" equipped with inertial locking mechanisms that stop the belt from extending off the reel during severe deceleration.