Operated by key outside and inside. Security deadbolts feature full 1 in solid core throw bolt, all metal mechanisms, anti-pry shield and pick-resistant 5-pin system. Door prep 2-1/8 in crossbore, 1 in edge bore, 1 in x 2-1/4 in latch face. Backset adjustable 2-3/8 to 2-3/4 in. Door thickness fits 1-3/8 to 1-3/4 in doors. Cylinder 5-pin. Faceplates of 1 in x 2-1/4 in round corner. Strikes of 1 in x 2-1/4 in round corner. Bolt 1 in throw. Reversible for right or left handed doors. ANSI/BHMA Grade 3.This double cylinder deadbolt is operated by a key on both sidesFeatures adjustable latch and deadbolt to fit all standard door preparationsAdd to a keyed knob or lever for additional security