"Quad-Seal" Ikelite camera controls are famous for their dependability. Each gland allows rotation and in-out travel of a 1/4-inch shaft (not included). Threads directly into a 3/8-24 tapped hole or using a 3/8-inch through hole and 0219.2 nut (not included). Choose length based on thickness of housing and length and travel of control shaft. Shaft, knob and nut not included.