Salisbury Electronic Lock for Designer Wood Locker Door are an excellent alternative to standard hasp and padlock. Electronic locks is a cost-effective and easy-to-use lock providing keypad access without the need for keys. It is designed with simplicity in mind, including programming. To open the lock, simply punch in a four (4) digit user code and turn the handle located just under the (10) digit keypad. A blue LED blinks once after each of the first (3) digit entries and blinks blue again if all four (4) entries are correct. Otherwise, it blinks red after the fourth entry if one or more digits were incorrectly entered. Salisbury Industries is an ISO 9001: 2008 certified company and has excelled in the field of manufacturing since 1936.