The WheelerA(R) Crowfoot Wrench for Standard & Low Profile Castle Nuts are professional-grade, hardened steel wrenches specifically crafted to stand up to the rigors of AR-15/LR308 assembly, maintenance, and modification; allowing you to tackle any AR building or maintenance task. Each wrench is purposely-built with precision to exact fitment allowing you to install handguards, muzzle devices, and barrels with confidence. FEATURES Innovative dual-ended wrench design performs multiple functions per wrench?. Compatible with XL F.A.T. Wrench or any other A 1/2'' drive torque wrenches?. Professional-grade, hardened steel construction withstands extreme Mfg: Wheeler Engineering