TacFire's AR15/M16 gas tube is constructed of stainless steel and is head/corrosion resistant treated. It is ideal for building your AR15/M16, replacement or upgrade part. The gas tube pins into the front sight or gas block. This model has a mid length.Our AR-15 /M16 mid-length gas tube is constructed of hardened stainless steel for strength and durability. The AR-15 /M16 Mid-length gas tube is heat and corrosion resistant to ensure consistent gas flow to help your rifle cycle properly. This AR-15 gas tube fits most pistol length gas systems. This is great if you're building an AR-15 /M16 or sourcing parts for replacement or upgrade. It Pins into front sight or gas block, No gunsmithing is required.