Samsung SHS-3321 Digital Door Lock, Black, Keyless, Electronic, Deadbolt DETAILS  Program up to 71 user codes and RF ID tags. Fits doors 35mm to 55mm thick. Automatic locking. Compatible with certain NFC items. Battery operated with emergency power contact. DESIGN  Samsung door locks have a sleek modern design which would complement any interior or exterior door in the residential home, apartment, or commercial business office building. EASY TO USE  Use the digital touchscreen numeric keypad to enter a password or RFID faster than you can turn a key. Shut the door and the magnetic sensor automatically locks the door for you. EASY INSTALL  Installs on standard 161 prep doors therefore no drilling (161 Prep is a cylindrical lock prep with a 2-1/8 hole at 2-3/4 backset, where the door edge prep is 1-1/8 x 2-1/4.), universal deadbolt to adjust between 60mm and 70mm, can be installed on the right or left hand side. SECURITY  Rigorously tested construction, random security code feature, bump and pick proof, intrusion alarm, PSB fire tested and fire detection sensor, anti tampering lock out. The lock has your back.