Item Type: Wireless Doorbell Material: ABS Color: Black Weight: Approx. 111g / 4oz Package List 1 x Doorbell 1 x Receiver 1 x Sticker 1 x English Manual 1Self Powered: This wireless doorbell is self generating electricity and can be self powered so you can use this doorbell without batteries. 2Work Principle: The doorbell has a built in power generation template, which is automatically converted into electrical energy when the finger is pressed and instantly sends out a wireless signal, and the indoor receiver automatically sounds the bell. 3No Punching and Wiring: This self powered wireless doorbell is no need for punching and wiring, simple installation. 4Sound Grade Increase Horn: Self powered wireless doorbell is with sound grade increase horn, ringtone coverage of 200. 5ABS Material: Self powered wireless doorbell is made of ABS material and can be widely used for home, restaurant, hotel and so on.