A receiver and a transmitter to be a wireless doorbell, do not need to plug. 300 meters straight distance, anti-interference, 4 gears volume and 36 chord music. It can be taken as a doorbell to let the sweet ring instead of knocking, or a pager convenient for the elderly and pregnant women to call for help. Features: Rear horn, loud voice. Adjustable ringtones and volume. 4 gears volume, 36 chord music. Strong penetration, long distance transmission, 300 meters of the straight distance. The transmitter has a waterproof design and meets IP44, extend service life. Suitable for ordinary buildings, villa, housing, hotel apartment, office area, etc. Specifications: Material: Plastic Color: White, Black (optional) Receiver: 3 x AA batteries (not included) Transmitter: 1 x 12V 23A battery (included) Item Size: Receiver: 95 * 65 * 25mm / 3.74 * 2.56 * 0.98in Transmitter: 75 * 51 * 20mm / 2.95 * 2.01 * 0.79in Package Weight: 150g / 5.29ounces Package Size: 120 * 90 * 70mm / 4.72 * 3.54 * 2.76in Packing List: 1 * Receiver 1 * Transmitter 1 * Doorbell Sticker 1 * Transmitter Double-sided Sticker 2 * Screws