Description: Wall plug in, no need battery, sensitive and stable signal reception, the maximum coverage distance is 80m, and a variety of scenarios are available, such as living room, kitchen, bedroom, balcony, or commercial office buildings, clubs, shops, restaurants, factories, etc. The doorbell switch and the receiver are wirelessly connected, avoiding wiring and making it easier Working principle: The transmitter is installed outside the door, the receiver is installed on the power socket, press the transmitter to rings the bell, the receiver will immediately rings the bell and flash the light to remind IP47 waterproof design, don't worry about rainy days, effectively prolong the service life of the doorbell 38 polyphonic ringtones, pleasant to the ears, built-in dual-tones stereo speakers, 4-level volume adjustable, clear and loud sound. Specification: Material: ABS plastic and electronic components Plug: US Size Chart: transmitter 6.8x3.7cm/2.68x1.46inch receiver 10x5.5cm/3.94x2.17inch Package Includes: 1x Doorbell Transmitter 1x Receiver 1x Nail Free Glue Note: 1. Please allow slightly error due to manual measurement. 2. Due to the difference between different monitors, the picture may not reflect the actual color of the item. 3. Wish you a wonderful on-line shopping!