For keyed exterior doors. Both knobs lock or unlock by key outside or turn button inside. All metal components. Solid steel latch assembly. Rust-resistant solid brass keyway for more security. Seamless 1-piece knob for extra strength. Square spindle for right or left handed installations. Easy installation. Cylinder drilled for construction keying. Door prep 2-1/8 in Crossbore, 1 in Edge Bore, 1 x 2-1/4 in Latch Face. Fits 1-3/8 to 1-3/4 in doors.