Practical UseIdeal for use as an alarm for those who need help quickly, such as the elderly, children, disabled, pregnant women or patients, sick, just press the call button to get timely and considerate care, it can also be used as a doorbell. Widely used in home, hospital, community, restaurant, office, etc. Easy to UsePlug the receiver into the power outlet where you need to be reminded, the waterproof transmitter can be worn as a pendant or placed at the bedside. The 90~250V mains powered receiver works with a low-power transmitter that enjoys a long standby time. 52 Alert Options & 80m Range52 alert sounds to choose from, with flashing LED alert. 4-level adjustable volume, max 110db ideal for the elderly. No switch is designed to avoid missing the important emergency alarm. Up to 80 meters range in open area (walls and other objects will reduce the range), no interference with other devices. Call ModePress the SOS button once (1-2 seconds), the receiver will alarm once. If you need continuous alarm, please press the SOS button several times. Low Battery Indication1, If no operation but the transmitter LED indicator light keeps flashing, means the battery is low, please replace the batteries; 2, The pairing between transmitter and receiver may be lost after replacing the battery, manually pair them to repair; 3, Use a flat screwdriver (not included) to pry the side of the transmitter to replace the battery. Quantity sold: 3 pieces Number of songs: 52 Body material: high quality ABS raw material + high quality brushed aluminum foil Working distance: 80 meters Working frequency: 433 Mhz Color: white Workplace: family community, restaurant, hospital, office building, etc. Power supply voltage: Receiver: 90~250V Transmitter: 3V 2032 battery Dimensions: Receiver: 81*81*45mm Front machine: 60*34.5*1 1.5mm Remarks: The receiver and transmitter can be paired one by one, and the corresponding ringtone can be set separately About chromatic aberration: The goods sold are all taken in kind, but due to different lighting, monitors, etc., there will be a little color difference, which is a normal phenomenon, not a quality problem! About size: The dimensions of the products sold are all measured manually. Due to different measurement methods and tools, there may be an error of 1-2mm, which is normal!becomeveryrich