Installation : 1. Use the Self-contained screws to install lock body, cylinder and door holder into the door edge or door frame. Proposed 5mm min. Installation distance from lock body to lock holder. 2. The loading spring is adjustable with the door's weight and door closer's power. 3. Dead bolts could change direction according to the Open Type. 4. Use a DC12V +/- 10% voltage. Push or turn the button, lock could automatic unlock after 1 second. Features: 1. It supports Electrical control or hand operation. 2. Has functions of high guard and high security, e.g. protect non-key's unlock after message report. 3. Fits for building intercom or access control systems. 4. Could be mounted in residential building, commercial housing, hotel, warehouse, school. 5. Can be used on Wooden / Metal doors.