Stainless steel fine hex bolt M10X85 (pitch 1.25) L size is indicated below the neck. M10P = 1.25 (fine pitch) is used in cars and motorcycles. Please use it for adjusting the mounting of the seat rails and other components. The finer pitch has a structured valley system than a coarse pitch for physical strength. This product is M10P = 1.25 fine pitch. Cannot be used in combination with coarse (P = 1.5). Please prepare nuts with the same pitch.