JBF National's knurled knob locking nose retractable plunger comes available in steel, 303 stainless steel, 316 stainless steel, and brass. A simple 90 degree twist engages the locking element, thereby holding the plunger in the retracted position until disengaged by a reverse twist, and the knurled rim allows for maximum grip regardless of grip situation. This retractable plunger (also known as an indexing plunger) also features a nylon thread coating to ensure ultimate thread locking in heavy vibration situations.