This is a TruGlo Gobble Stopper Extreme Choke Tube for 12 Gauge Mossberg AccuChoke. TruGlo's best selling turkey choke! Precision-machined ported turkey tube. Accepts all turkey loads, including Hevi-Shot. Wrench-free installation. No steel shot. Endorsed by the National Wild Turkey Federation. This choke tube is for Mossberg 3.5 AccuChoke 835 Ulti-Mag and 935 Magnum shotguns.