The GrovTec Two-Piece Barrel Band Swivel Set has an Allen wrench for installation, a .75" wood screw swivel stud for the butt stock and a two-piece magazine band, sold by diameter .8-.85" for this set. Best of all, there are two locking swivels with a 1" loop that have the easy-adjust thumbscrew for security and function. Install the best locking swivel sling loop you can get to make your next trip to the field a real joy.Our 2-piece barrel band sets fit almost any firearm from a .22 rimfire magazine tube of 0.42 inches diameter up to shotgun barrel with a 0.9 inches diameter.