Forward Controls Design Forged M16 Threaded Stripped Upper Receiver Anodized Black. URF-F has relief cuts/chamfers on the area above the charging handle (before 1913 rails start) for better accessibility of a flip up BUIS's sight stalk / flip up element. Type 3 hard coated in black. Like TDP spec A3 upper receivers URF-F can accommodate a forward assist but does not come installed with one. Specifications for Forward Controls Design Forged M16 Threaded Stripped Upper Receiver: Manufacturer: Forward Controls Design Color: Black Finish: Anodized Fabric/Material: 7075-T6 Aluminum Gun Make: AR Platform Gun Model: M16 Package Contents: Forward Controls Design Forged M16 Threaded Stripped Upper Receiver What firearm models does the manufacturer say Forward Controls Design Forged M16 Threaded Stripped Upper Receiver is compatible with? The manufacturer suggests that Forward Controls Design Forged M16 Threaded Stripped Upper Receiver is compatible with M16Forward Controls Design URF-F: Forged M16 Threaded Stripped Upper Receiver Anodized Black