AR-15/M16 Carbine Length gas tube is constructed of Hardened Stainless Steel for strenght and durability. The carbine gas tube is Heat & Corrosion resistant to ensure consistent gas flow to help your rifle cycle properly. Please selelect length according to your AR-15 gas system length. 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.