3/4" Twist Lock Plunger Latch - PIERCE twist lock plunger pins are used on applications where a self-locking mechanism is needed. Traditionally, plunger pins are used in the towing field on wheel lifts and wrecker slings. To Use: Drill a 3/4" hole then weld the pin into the space. Activate by rotating the head. Grease the pin regularly for optimal performance. Features: Easily welded into position for maximum versatility. Design incorporates a protective shoulder to prevent binding when welding the plunger into place. Use on sling arms, wheel lift arms, dump kits, etc.