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 crio plus (sbe ii, m-2, current sport 11, super sport, cordoba, montefeltro).Approved: Steel,Lead,Non-ToxType: Choke TubeGauge: 12 GaugeConstriction Type: Extended RangeConfiguration: Crio PlusFinish: BlackConstrictiondiameter: .667Chokes Included: 1Recommended For: 40+ ydsMaterial: 17-4 Stainless SteelPorted: Yes