Introducing the Luth-Ar LLC AR-15 Mba-3/Mba-4 Carbine Castle Nut expertly crafted to enhance your firearm's performance. Designed specifically for AR-15 models this durable castle nut is constructed from high-quality black steel ensuring long-lasting strength and reliability. Its sleek black finish not only complements the aesthetics of your firearm but also offers superior corrosion resistance. An essential component for securing the buffer tube assembly to your AR-15 carbine this castle nut guarantees a secure fit and optimal function. Upgrade your AR-15 with the trusted craftsmanship of Luth-Ar and experience the precision and reliability you demand.