92670 : Magazine Clamp W/Sling Swivel for Mossberg 930 12Ga Black
G&P Steel Barrel Clamp & QD Sling Mount Set for Shotguns, Accessories & Parts, External Parts, Sling Adapters - Evike.com Airsoft Superstore
Amazon.com: Gotical-Shotgun Mag Clamp with Sling Swivel 12 Gauge 1" Pack of 2 Shotgun Clamp New 1 Inch Shotgun Clamp Glass-Nylon Composite Used to Attach a Sling-Swivel to Some Shotguns (Black, 2Pcs)
Mesa Tactical Shotgun Barrel Clamp Sling Mount with QD Sling Swivel
Shotgun 12ga. Mag Tube Two Piece Barrel Band Locking Swivel Set - GTSW