JL Billet Barrel Nut AR15 1.375 inch OD Black. 375" OD These barrel nuts are designed to use with our handguards but can be used with other handguards on the market as well. JL Billet rails are precision bored to 1.375" ID to fit these. They can be torqued using a 1 1/8" crows foot. Specifications for JL Billet AR15 Barrel Nut/1.375 inch OD: Manufacturer: JL Billet Color: Black Gun Model: AR-15 Fabric/Material: 7075-T6 Aluminum Weight: 0.8 lb Country of Origin: USA Features of JL Billet AR15 Barrel Nut/1.375 inch OD AR 15 steel barrel nut for use on JL Billet M-Lok and Keymod handguards Package Contents: JL Billet AR15 Barrel Nut/1.375 inch OD What firearm models does the manufacturer say JL Billet AR15 Barrel Nut/1.375 inch OD is compatible with? The manufacturer suggests that JL Billet AR15 Barrel Nut/1.375 inch OD is compatible with AR-15JL Billet JLB-AR15-BN: Barrel Nut AR15 1.375 inch OD Black