Feature: 1. 150m/164yd wireless range, ideal for large houses with multiple entrances or floors, offices, hotel services and other areas with large spaces. 2. Built in micro kinetic energy generation power module, finger press can generate electricity. 3. Power is generated by pressing to drive the wireless signal, no battery, no wiring, easy installation. 4. Simple installation, no complicated operations, convenient and easy for you to use. 5. With the use of high quality ABS material, high performance and long service life. Specification: Item Type: Wireless Doorbell Material: ABS Power Supply Voltage: US Plug 100-230V AC Power Consumption: 0.25W Quantity of Songs: 38 Transmission Distance: ≥ 150m/164yd (open area) Operating Frequency: 433MHZ. Package List: 1 x Transmitter 1 x Receiver1 x Adhesive Tape1 x Manual Note: When installing the transmitter, please avoid the objects that can easily affect the signal transmission, such as iron doors and iron frames