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. The Adapter Plate is 1.700" long x .975" wide.