ODIN Works .223/5.56 Barrel Nut Black. Specifications for ODIN Works AR-15/AR-10 Barrel Nut: Manufacturer: ODIN Works Color: Black Gun Model: AR-15 Condition: New Package Contents: ODIN Works AR-15/AR-10 Barrel Nut What firearm models does the manufacturer say ODIN Works AR-15/AR-10 Barrel Nut is compatible with? The manufacturer says that ODIN Works AR-15/AR-10 Barrel Nut is compatible with AR-15 AR-10ODIN Works ACC-BRN-223: .223/5.56 Barrel Nut Black