Disclosed is an improved password lock, comprising a housing, a lock case, a password box, and a tongue; the housing is composed of a shell and a panel; the panel is fixed on the top surface of the shell to form an accommodating cavity of the housing; the middle part of the lock case is rotatably sleeved at one side of the housing; the password box is installed in the accommodating cavity of the housing, and the password box is cooperatively linked with the lock case; and the tongue is fixedly sleeved on a penetrating end, penetrating through the housing, of the lock case. The lock case can drive a slide block in the password box to move horizontally for changing a password, and therefore the operation is convenient.

A dual locking system including a combination mechanism and a key mechanism is provided, including a control plate to control access to the key mechanism. When the control plate is positioned in a blocking position, the control plate blocks access to the key hole of the key mechanism. The control plate can be released from the blocking position by turning the dials of the combination mechanism to the correct combination. The released control plate can be moved to an exposure position, which allows access to the key hole.

A dual locking system including a combination mechanism and a key mechanism is provided, including a control plate to control access to the key mechanism. When the control plate is positioned in a blocking position, the control plate blocks access to the key hole of the key mechanism. The control plate can be released from the blocking position by turning the dials of the combination mechanism to the correct combination. The released control plate can be moved to an exposure position, which allows access to the key hole.