Overall it is a CNC aluminum. RMR Mini red dot sight-only mount base. Angus RMR mount base-Marui Mk23 SOCOM-only-trisicom RMR typed it site dedicated-2 long screws for mounting the 2 short screws with sandblast, black anodized, machined aluminum--slide the hole drilling is required-is part of advanced * Mary soucom-long-range custom, over long distances and the aim but not site? *, To respond to requests trisicom RMR mount base-typed it site. * Find solid mass hit.