Double sided code lockFits in Both Right & Left Opening Doors It does not require wires batteries. This lock is perfect for outdoor use.Item Features- Install on right or left edge of the door- Suitable for offices, classrooms, apartments, etc.- Suitable for door between 30mm and 60mm thick.- Suitable for a variety of door installations, such as wrought iron doors, wooden doors, steel doors, patio doors- Simple installation, quick operation, outdoor use, waterproof, rainproof, sunscreen, fireproof, no rust, environmental protection.- detailed installation guide & operation Keystroke function 12 buttons including 10 number keystroke and 4 letter keystroke.Special key-button "C", eliminate misinput, easily use.Numeral key-choose 4-7buttons to set the password in 13 keystroke except button "C".