Hex Rear Binding Post - Brass - Short - Assembly Includes (1) Brass Hex Rear Binder .312" (5/16") Hex Size X .440" Long, (2) Black Nylon Shoulder Washers, (2) #8 Brass Flat Washers, (1) 8-32 X 1/2" Button Head Cap Screw. Can Be Mounted In Either A Vertical Or Horizontal Position.