Obsidian Arms OA-15C Billet Upper Receiver Black. Machined from 7075 T6 Aluminum Billet for a stronger better fitting more unique looking receiver. Specifications for Obsidian Arms OA-15C Billet Upper Receiver: Manufacturer: Obsidian Arms Caliber: Universal Overall Length: 7.65 in Muzzle Device: None Finish: Black Hard Coat Anodized Color: Black Fabric/Material: 7075 T6 Aluminium Gun Rail: Picatinny Gun Type: Rifle Gun Make: AR Platform Gun Model: AR-15 Weight: 8.8 oz Condition: New Bolt Carrier Group Included: No Charging Handle Included: No Mount Type: Rail Country of Origin: USA Features of Obsidian Arms OA-15C Billet Upper Receiver Removable Shell Deflector included No forward assist No ejection port cover Enlarged Ejection Port for Big Bore calibers such as .450 Bushmaster .458 SOCOM .50 Beowulf etc. Will work with any standard AR-15 lower Will work with any standard AR-15 barrel Billet 7075 T6 Aluminum Alloy Package Contents: Obsidian Arms OA-15C Billet Upper Receiver What firearm models does the manufacturer say Obsidian Arms OA-15C Billet Upper Receiver is compatible with? The manufacturer suggests that Obsidian Arms OA-15C Billet Upper Receiver is compatible with AR-15Obsidian Arms OA-15C-UR-BLK: OA-15C Billet Upper Receiver Black