●Set comes in 4 stainless steel mightybolts, 4 convertible Knobs, 4 track nuts, 4 socket head cap screws. All parts are standard 1/4-20 thread. The stem diameter is 1/4" (0.635 mm). The screw length is 1.5 inches ●Our set Compatible with GearTrac, MightyMount and standard kayak accessory tracks.