Manganese Phosphate (Mil-Spec DTL 16232G)is a friction reducing, corrosion resistant, anti-galling bolt carrier group coating also known as Parkerizing, used to improve lubrication in sliding actions. It offers wear resistance and reduced wear during metal to metal contact. It has been developed to retain and enhance the performance of corrosion resistant oils and waxes. Manganese Phosphate is not a surface coating. It's a conversion coating that penetrates the surface and becomes part of the material. Cryptic's phosphate has a smooth rich black appearance produced with a fine, dense microcrystalline structure. Making it a highly-sought-after phosphate bolt carrier group coating.