personal protective equipment which protects the wearer against sudden accelerations or decelerations, an assembly of straps with a securing buckle, adjusting devices and attachments which is capable of being anchored to a power-driven vehicle and is designed to diminish the risk of injury to its wearer, in the event of collision or of abrupt vehicle deceleration, by limiting the mobility of the wearer's body. Such an assembly is generally referred to as a "belt assembly", a term also embracing any device for energy absorption or belt retraction.