The Highland SS Book Screw is designed to attach various parts of gear to other items. They can be used to attach wings to plates, to hold pads on plates, pockets into place where you desire and so much more. The Highland SS Book Screw comes as a complete set, male & female. Made from Stainless Steel and includes a friction O-ring to keep held in place. The Highland SS Book Screw is made to fit through 3/8" holes.