This optic adapter plate supports the use of docter, meopta, eotech, insight, noblex red dot sights on the ruger-57 pistol.Also fits the truglo tru-tec micro tg8100b.The plate is precision cnc machined from 6061-t6 aircraft aluminum with a matte black hard-coat finish for strength and durability.Simply place the adapter plate onto slide and secure it using the two #6-32 screws provided.Tighten the screws firmly (30-50 in-lbs.) using a torx t-15 wrench (not included).Install the optic onto the adapter plate by following the sight manufacturer's mounting specifications (sight not included).The adapter plate is 1.700" long x.975" wide and weighs.2 ounces.This genuine ruger factory accessory is made in the usa.Finish: Matte BlackMaterial: AluminumOne Or Two Piece: one pieceMount Type: Screws