The silver multi-tone gong with an acrylic disc in a satin glass look features a stepless volume control. It can be switched from melody to alarm tone, making it ideally suited for use with motion detectors, allowing a melody to be triggered during the day in a store and an alarm tone at night. A dual call distinction ensures optimal access control. When connected to a doorbell transformer, illuminated doorbell buttons can be used; for battery operation, we recommend non-illuminated ones.