Fits: Beretta 682, Some 687 models, Silver Hawk, DT10, Some 391 models; For 12 gauge shotguns; Tubes are longer and slimmer than conventional Mobilchoke tubes; Thanks to the elongated cone they minimize pellet deformation and improve shot patterns; The various versions are fully interchangeable on 12 gauge guns with Optima Bore barrels; These choke tubes are for 12 gauge shotguns with the Optima-Choke system only