Tacfire AR Upper Receiver Vise Block Black. It allows for safe clamping and will help to prevent any type of distort or damage to the Upper receiver. Great to use when performing your regular maintenance repairs or weapon assembly. Fits most standard Mil-Spec AR-15/M4 style rifles . Specifications for Tacfire AR Upper Receiver Vise Block: Manufacturer: TacFire Gun Model: AR-15 Gun Type: Rifle Color: Black Condition: New Length: 4.75 in Package Contents: Tacfire AR Upper Receiver Vise Block What firearm models does the manufacturer say Tacfire AR Upper Receiver Vise Block is compatible with? The manufacturer says that Tacfire AR Upper Receiver Vise Block is compatible with AR-15Tacfire TL009: AR Upper Receiver Vise Block Black