Practical & Reliable: Perfect as an alarm for those who need help quickly, such as the elderly, children, disabled, pregnant women, or sick individuals. Simply press the call button to get timely and attentive care 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). The use of 16-bit coding to eliminate interference from other devices ensures it works virtually anywhere in your home. Multiple Alarm Options: Choice of 45 sounds (36 melodic sounds and 9 alarm sounds) and three alarm modes (Sound + Light, Sound only, Light only). The sound volume can be adjusted on 3 levels, max. 110db, perfect for the elderly. No power switch is designed to avoid forgetting to turn it on, as it could miss an important emergency call (if not used for a long time, remove the batteries to preserve their lifespan). Convenient Transmitter Placement: The waterproof transmitter can be worn as a necklace or placed by the bedside. The receiver can be attached to the wall, placed freely on the desk, or carried in the caregiver's pocket. Low Battery Warning: 1. Without operation, but the device's indicator light flashes or emits an abnormal sound, replace the battery. 2. The pairing between the transmitter and receiver may lose contact after the battery has been replaced. The items are not defective. Manually pair them to fix them. The receiver is powered by 3 x AAA batteries (not included). The transmitter is powered by 1 x button cell battery (included).