Outerwild AR15 Billet Upper Receiver Black Anodize. Machined from a solid brick of 7075-T6 aluminum hand deburred tumbled and hard coat anodized. Accepts all Mil-Spec components and fits all Mil-Spec dimensions lower receivers. Outerwild ensure that every upper is well within spec and will function perfectly for your build. Specifications for Outerwild AR15 Billet Upper Receiver: Manufacturer: Outerwild Color: Black Finish: Anodize Fabric/Material: 7075-T6 Aluminum Gun Make: AR Platform Gun Model: AR-15 Package Contents: Outerwild AR15 Billet Upper Receiver What firearm models does the manufacturer say Outerwild AR15 Billet Upper Receiver is compatible with? The manufacturer suggests that Outerwild AR15 Billet Upper Receiver is compatible with AR-15Outerwild 4022-0909-001-O: AR15 Billet Upper Receiver Black Anodize