U-Bolt 1 inch Ball Handlebar Mount with Security Pin-Lock Short Double Socket Arm and GoPro Hero Camera Adapter (sku 30638)U Bolt 1 inch Ball Handlebar Mount with Security Pin Lock Short Double Socket Arm and GoPro Hero Camera Adapter. This mount features a u bolt base with a 1 inch rubber ball, a short double socket arm with mixed combination 7 Pin Lock and key together with a 1 inch ball custom GoPro Hero camera adapter. The u bolt base is designed to sit at right angles to the mounting rail and the zinc coated metal u bolts accommodate rails from 12. 7mm to 31. 7mm in