1ABS Material: This wireless doorbell is made of premium ABS material, white appearance, strong and practical, can be used for a long time. 2Large Coverage Area: With sound grade horn, operating range up to 200 in open area, offer you fast indication, which ensures you to hear the bell and answer the door in time. 3Self Powered Design: This self powered doorbell dose not require battery for life, no need for line, no need for punching, easy to install. 4Usages: Built in power generation template, when pressed, automatically converted into electricity, send out a wireless signal instantaneously, and indoor receiver will ring automatically. 5Multiple Applications: This wireless door bell can be used for home, office, apartment, school, villas, warehouses, hotel, factory, hospital or other places.