GEM Buzzer Bridge Rectifiers can serve as an added security to your access control system. The SM1224BZ-1A has two combined features: an In-line power controller with built-in surge protection and a piezo buzzer beeps every time the door is being activated to open. The SM1224-TBZ includes adjustable relock time delay and provides countdown beeps until the door is locked. These models can be connected to fail-secure or fail-safe electrified locks.