Flush mount, stainless steel tubes available for the many shotguns using the popular Win-Choke thread size and standard Tru-Chokes, plus Remington, Beretta/Benelli, Browning Invector Plus, and Mossberg 835 A Ultra Mag. These tubes can be used with magnum and steel shot loads. Tru(TM)-Choke Thinwall tubes are recommended for 2A 3/4" Lead Shot loads ONLY. All X-Full and Turkey constrictions are for use with Lead and Hevi-Shot ONLY! Mfg: Carlsons SPECS: 1704 Stainless steel, heat treated. Available for 20 gauge, depending on model. Tru-Choke(TM)-style (T-C):.675"-44 tpi fits 20 ga. Tru-Choke-style. Win-ChokeA(R)-style: .687"-32 (20 ga.) fits barrels originally equipped with Win-ChokeA(R), Browning Invector, Mossberg Ac