BLACKHAWK! Magnum Split Band Swivel Set Fits most Picatinny spec rails Protects unused rail areas from damage Shields operator from sharp rail edges and heat Locks on with patented Rail-Lok integral locking mechanism Low profile, aggressive grip surface for better weapon control LOK-DOWN Swivel Set Mounts on magazine tubes .630 to .675 diameter Mounts on barrels of some Rugers and Brownings Mounts on some barrels of .410 shotguns Offered as 1" and 1.25" models