12 Gauge fits Mossberg 500, 535, 930, and Maverick 88 threaded barrels. Also compatible with Smith & Wesson, Savage, & U.S. Repeating Arms (Win-choke) and Browning Invector interchangeable choke models. 20 Gauge chokes fit: Mossberg 500, 505, 510 Mini, and Maverick 88 threaded barrels. Also compatible with Smith & Wesson, Savage, & U.S. Repeating Arms (Win-choke) and Browning Invector interchangeable choke models.