The TPR UniLock™ is the only trailer-postioned vehicle restraint that can automatically remove "RIG Wedge" pressure. RIG Wedge is caused when the trailer is pushed forward during loading/unloading and the trailer's Rear Impact Guard (RIG) applies so much pressure to the restraint's hook that the truck driver must reverse the trailer in order to release the restraint. The UniLock has an advanced cam design that first rotates the hook away from the RIG to remove the pressure, and then rotates down to a stored position.