The Fortis Manufacturing K1 Lightweight Enhanced Castle Nut provides reliable buffer tube retention for AR15 platforms with anodized finish for enhanced durability and corrosion resistance.Fortis K1 Lightweight Enhanced Castle NutDesigned for AR15 buffer tube assemblyAnodized finish for superior protectionLightweight enhanced designPrecision manufactured by Fortis ManufacturingEssential component for AR15 builds and maintenance offering dependable performance and long-lasting protection in a lightweight package.