The ruger optic adapter plate supports the use of burris fastfire and vortex viper/venom red dot sights on the ruger-57 pistol.The plate is precision cnc machined from 6061-t6 aircraft aluminum with a matte black hardcoat 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.Made in the usa.Adaptor Type: Red Dot SightFinish: BlackMaterial: AluminumMount Type: Screws