LanTac USA LLC M-Spec Carbine Gas Tube, Fits AR 15 with Carbine Length Gas System, Stainless Steel Finish, Silver 01-MSPEC-GT-CRBN Lantac M-SPEC Gas Tubes are Precision manufactured from 306 stainless steel extruded tube. Lantac's M-SPEC gas tubes offer the shooter a mil-spec, high quality product at a competitive price point.