Electric Release Door Lock, ZOTER Electric Lock with Key NO Mode for Video Door Phone Intercom Can suit both Left and Right hand door (by rotating the lock 180X) NO (open when powered) Fail Secure Operating Mode Can directly connect to outdoor camera of Electric Video Door Phone and open door without connect to extra DC 12V power supply (if the video door phone supports NO unlocking mode) Support manual unlocking, 3 keys included Suitable for : home, offices, schools, hotels, factories, warehouses, etc