Headlock Bolts eliminate the need for lock washers, Period. That's because each Headlock Bolt features 24 equally-spaced, stainless steel teeth serrations that bite into and hold onto the attaching surface–eliminating the need for lock-washers. 16 per Package. Includes a ball-head/hex-key socket-installation tool that makes it easy to get them started. 410 stainless steel. Minimum 180,000 PSI tensile strength. 24 equally spaced clockwise teeth.