Stern Defense SD AR15 Assembled Upper Receiver Black 12.5x3.5x3.5in 010-UPPER RECIEVER-KK-P. Machined from 7075-t6 aluminum and hard-coat anodized. Mil-spec dry film lube in the bore. Specifications for Stern Defense SD AR15 Assembled Upper Receiver: Manufacturer: Stern Defense Color: Black Finish: Hard Coat Anodized Fabric/Material: 7075-T6 Aluminum Gun Make: AR Platform Gun Model: AR-15 Condition: New Features of Stern Defense SD AR15 Assembled Upper Receiver Sturdy construction Package Contents: Stern Defense SD AR15 Assembled Upper Receiver Dust cover and forward assist What firearm models does the manufacturer say Stern Defense SD AR15 Assembled Upper Receiver is compatible with? The manufacturer suggests that Stern Defense SD AR15 Assembled Upper Receiver is compatible with AR-15Stern Defense 010-UPPER RECIEVER-KK-P: SD AR15 Assembled Upper Receiver Black 12.5x3.5x3.5in