1.Cast alloy integrative structure, firm and durable 2.High quality with competitive price 3.Very easy to operate, for office, house and apartment 4.master passwords and sub passwords, which are easy to manage 5.Change master passwords freely 6.Master passwords can be used to add or cancel any sub password 7.One-key opening function: freely press any key to open the lock 8.Input wrong passwords for three continuous times, it will stop for 10 seconds without any operation 9.Three mechanical keys for emergency use 10.Performance index: Power supply: 6V, 4 standard AA alkaline batteries Battery life: open more than 15000 times under normal circumstance Open time: within 5 seconds after inputting correct passwords 11.Low voltage warning: when CPU working voltage is less 4.5V, when you open the lock after the screen light turns on, it will alert by "di di" tone with the red light flashing 12.It can still open the lock for 100 times 13.There are three choices for you to adopt: single-latch, four-latch, and five-latch