We offer a superior bolt securing system that provides safe locking for bolted joints even when exposed to severe vibration and dynamic load. The unique aspect of Nord-Lock® is that it doesn't attempt to prevent relative motion, but instead only allows this motion to tighten rather than loosen the bolt. This is accomplished with a pair of washers whose inner surfaces act like cams with a greater ramp angle than the helix angle of the screw threads. On the opposite side are serrations that grip the bolt head and the mating surface. If the bolt attempts to move in the direction of loosening, a wedge is created and tension is actually increased.