Guntec Castle Nut Extreme Duty Features The Guntec USA Castle Nut is built with an enhanced wide design specifically engineered for extreme strength and durability compared to a standard factory castle nut. Machined from steel the nut resists the stress and wear that comes from repeated stock adjustment and recoil transfer through the buffer tube. The skeletonized extended design not only reduces weight slightly but also improves grip when tightening or loosening the nut with a wrench or armorer s tool. This reinforced geometry helps the nut stay properly torqued over the life of a rifle build. Finished in a durable black nitride coating the castle nut resists corrosion and wear far better than a bare steel finish standing up to years of handling and environmental exposure. It is designed to fit both mil-spec and commercial buffer tubes making it a versatile upgrade regardless of which buffer tube standard a particular AR-15 build uses. Made in the USA this castle nut reflects the quality control Guntec USA applies across its line of AR-platform components. This Extreme Duty Castle Nut is a straightforward durable upgrade for any AR-15 buffer tube assembly for sale at GrabAGun. Guntec Castle Nut Extreme Duty Specifications Manufacturer: GunTec Material: Steel Finish: Black Nitride Type: Wide Extreme Duty Castle Nut Compatible Hosts: Mil-Spec and Commercial Buffer Tubes Available At: GrabAGun