S&W 6" barrel .177 caliber Matte black shroud Fits Umarex-made Smith & Wesson 586 CO2 revolvers Increases velocity over the 4" barrel Easy to install No machining involved Includes shroud, barrel & screw Does not fit S&W firearms or airsoft guns If you've got an Umarex S&W 586 CO2 revolver with a 4" or 8" barrel, then this 6" one will make your collection complete. The longer the barrel on a CO2 gun, the greater the velocity.