DPMS Nitride Gas Tube Mid-Length. Whether you are keeping a spare on hand or repairing your AR-15 DPMS has everything you need. Specifications for DPMS Nitride Gas Tube: Manufacturer: DPMS Finish: Nitride Gun Make: AR Platform Gun Model: AR-15 Package Contents: DPMS Nitride Gas Tube What firearm models does the manufacturer say DPMS Nitride Gas Tube is compatible with? The manufacturer says that DPMS Nitride Gas Tube is compatible with AR-15DPMS DP51655151919: Nitride Gas Tube Mid-Length