Spikes Tactical Upper 5.56 16in CHF Midlength w/ 13.2in BAR2 Rail. We maintain our high standard of tolerances and attention to detail as the uppers we use for complete rifle builds. Every built upper and complete gun is test fired before leaving our facility for function check before it reaches you. We offer several rail choices and rail lengths. Features/Specifications: 10 BAR2 Rail. 7075 T6 Barrel Nut. 6061 T6 Rail. Continuous Top Rail. Free Floating 1 Piece. Q.D. Attachment Points. Low Profile Gas Block. Solid Billet Steel. .750 I.D. Mid Length Gas Tube. Black Nitride Inside and Out. Gas Tube Roll Pin. Charging Handle. Forged Aluminum. Mil-Spec Type 3 Coating. Phosphate M16 Complete BCG. Phosphate Coated. Laser Engraved with ST Spider logo. High Pressure Tested (HPT). Magnetic Particle Inspected (MPI). A2 Flash Hider. 1/2in Crush Washer. Features/Specifications: 9in SAR3 Rail. 7075 T6 Barrel Nut. 6061 T6 Rail. Continuous Top Rail. Free Floating 1 Piece. Q.D. Attachment Points. A2 Front Sight Base Pinned. Front Sight Post. FSP Detent. FSP Detent Spring. Mid Length Gas Tube. Black Nitride Inside and Out. Gas Tube Roll Pin. Charging Handle. Forged Aluminum. Mil-Spec Type 3 Coating. Phosphate M16 Complete BCG. Phosphate Coated. Laser Engraved with ST Spider logo. High Pressure Tested (HPT). Magnetic Particle Inspected (MPI). A2 Flash Hider. 1/2in Crush Washer. Features/Specifications: 12 SAR3 Rail. 7075 T6 Barrel Nut. 6061 T6 Rail. Continuous Top Rail. Free Floating 1 Piece. Q.D. Attachment Points. Low Profile Gas Block. Solid Billet Steel. .750 I.D. Mid Length Gas Tube. Black Nitride Inside and Out. Gas Tube Roll Pin. Charging Handle. Forged Aluminum. Mil-Spec Type 3 Coating. Phosphate M16 Complete BCG. Phosphate Coated. Laser Engraved with ST Spider logo. High Pressure Tested (HPT). Magnetic Particle Inspected (MPI). A2 Flash Hider. 1/2in Crush Washer. Specifications for Spikes Tactical 5.56 Midlength Cold Hammer Forged 16in Upper Receiver: Manufacturer: Spikes Tactical Caliber: 5.56x45mm NATO Barrel Length: 16 in Color: Black Gun Model: AR-15 Gun Make: AR Platform Magazine Included: No Country of Origin: USA Package Contents: Spikes Tactical 5.56 Midlength Cold Hammer Forged 16in Upper Receiver What firearm models does the manufacturer say Spikes Tactical 5.56 Midlength Cold Hammer Forged 16in Upper Receiver is compatible with? The manufacturer says that Spikes Tactical 5.56 Midlength Cold Hammer Forged 16in Upper Receiver is compatible with AR-15Spikes Tactical STU5435-R3S: Upper 5.56 16in CHF Midlength w/ 13.2in BAR2 Rail