At the time of going to press, we supply 2 types of locking wheel nuts for Sprites & Midgets. Not suitable for original steel wheels, use only with replacement alloy wheels. The TriLock system uses a socket with 3 pins that are uniquely matched to the TriLock locking nuts. The SupaLock system uses 8 offset grooves cut into the nut head that uniquely match the SupaLock socket.