Guntec USA AR-15 Billet Upper Receiver w/Charging Handle and Forward Assist Ejection Door Assembly

Guntec USA AR-15 Billet Upper Receiver w/Charging Handle and Forward Assist Ejection Door Assembly. 223 / 5.56 Cal T6 6061 Billet 1913 Picatinny Rail Flat Top Manufactured From Solid Block Of Billet Aluminum M4 Feed Ramp MIL-A-8625 TYPE III Anodizing Will Match Up With Any Brand Lower Receiver AcceptsMil-Spec Ejection Port Door Kit And Forward Assist Kit(Both Are Included) Slim Profile Shell Deflector Specifications for Guntec USA AR-15 Billet Upper Receiver: Manufacturer: Guntec USA Color: Black Finish: Anodized Fabric/Material: T6 6061 Billet Caliber: 5.56x45mm NATO Gun Model: AR-15 Package Contents: Guntec USA AR-15 Billet Upper Receiver What firearm models does the manufacturer say Guntec USA AR-15 Billet Upper Receiver is compatible with? The manufacturer says that Guntec USA AR-15 Billet Upper Receiver is compatible with AR-15GUNTEC USA GT-UPPER-3: AR-15 Billet Upper Receiver w/Charging HandleForward Assist Ejection Door Assembly