According to the unlock pattern
3. password padlock: because key padlock for each higher open rates, especially the small padlock, mutual opening rate job do not apply.
Thus developed the password padlock. Features: up to 10000 passwords.
1, stainless steel padlocks: antioxidant ability than such padlock features a strong, suitable for outdoor, but because of the difficulty, and high cost, domestic use is less. 2, copper padlocks: lock the main materials are copper, using the more common types of mainly small brass padlock, 40mm size, mainly copper prices higher.
3 iron padlock using very general.