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 carbine length.Our AR-15 /M16 carbine length gas tube is constructed of hardened stainless steel for strength and durability. The carbine 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 carbine 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.