Hevi-choke turkey are available in 12 and 20 gauge, in ported and non-ported versions, hevi-choke choke tubes help you squeeze every bit of performance from your hevi-shot ammunition.*warning: extreme range choke tubes are not recommended for steel pellets larger than bb or excessive speed of more than 1550 fps.Use mid-range choke tube for those applications.Compatible with mossberg (835,935).Approved: Steel,Lead,Non-ToxType: Choke TubeGauge: 12 GaugeConstriction Type: Extended RangeConfiguration: MossbergFinish: BlackConstrictiondiameter: .676Chokes Included: 1Recommended For: 40+ ydsMaterial: 17-4 Stainless SteelPorted: Yes