Complete M15 A4 Flattop Upper Receiver with forward assist and port door. Precision machined form high tensile strength 7075 T6 aluminum forgings, hardcoat anodized.
M-15 Uppers use 7075-T6 Aluminum.
Thread Size: 1-1/4" X 18 UNF-3A
Caliber: 6.8mm SPC II
Finish: Hard Anodized Aluminum, Manganese Phosphated Steel