For keyed exterior doors. Both knobs lock or unlock by key outside or turnbutton inside. DOOR PREP: 2-1/8 in Cross Bore, 1 in Edge Bore, 1 in x 2-1/4 in Latch Face. BACKSET: 2-3/8 in - 2-3/4 in adjustable. DOOR THICKNESS: 1-3/4 in doors standard and 2-1/4 in doors optional. CYLINDER: 5-pin SMT optional. FACEPLATES: 1 in x 2-1/4 in round corner. STRIKE: 2-1/4 in full lip. BOLT: 1 in throw. Nickel plated. HANDING: Reversible for right or left hand doors. ANSI/BHMA: Grade 2. Locksets with "SmartKey" (denoted SMT) feature allows,in 3 steps, locks to be re-keyed to a spare set of keys. When the spare keys are done being used, the lock can be re-keyed back to the original set of keys; can continually be re-keyed.