Practical ReliableIdeal as an alarm for those who need help quickly, such as the elderly, children, disabled, pregnant women or sick people, just press the call button to receive attentive care, in a timely manner and without shouting. It can also be used as a doorbell. Long range Up to 180 meters range in open area (walls and other objects will reduce the range), and the use of 16-bit encoding to eliminate interference from other devices allows it to work virtually anywhere in your home. More Alert Options 45 sound choices (36 melody sounds and 9 alarm sounds ) and three alert modes (Sound + Light, Sound only, Light only). Sound volume adjustable in 3 levels, max. 110db ideal for the elderly. No power switch is designed to avoid forgetting to turn on, because it could miss an important emergency call (if not in use for a long time, remove the batteries to preserve the duration life). Convenient placementtransmitter The waterproof transmitter can be worn as a pendant or at the bedside. The receiver can be wall-mounted, free-standing on the desk, or carried in the caregivers pocket. Low battery indication 1, Without operation, but the device indication light continues flashing or producing abnormal sound, please replace the battery; 2, The pairing between transmitter and receiver may lose contact after replacing the battery, the elements are not faulty, just manually pair them to fix. Receiver powered by 3 AAA batteries (not included); transmitter powered by 1 x button battery (included).