IMPORTANT: Please double check that you've selected the correct Gas Block Size and Gas Tube Length.Save time and money with this gas system assembly. Available in Pistol, Carbine, Mid and Rifle lengths, this is a great way to get good quality components, save a few bucks and not have to deal with the tedious task of pinning the gas tube into the gas block.Discount Gas Block* Fits .750 standard AR/M4 barrels* Mounts with two set screws* Phosphate coated 1018 steelStainless Steel Gas Tube Pistol, Carbine, Mid or Rifle lengths available Stainless steel construction Beveled alignment hole Lifetime Warranty