Wireless intercom doorbell no wiring no network required built-in wireless signal two-way intercom hands free supports wireless remote unlocking Wireless doorbell supports wireless unlocking and two-way voice intercom Adopting 433MHz public channel, with long wireless distance and strong transmission(about 800-1000 meters in open space, indoor 1-6 floors) 18650 battery powered, low-power consumption, ultra-long standbytime. Wireless unlocking box design, Tap the key to unlock, easy to install and portable size. Colour: Black Material: ABS Package Contents: 1 set of Wireless intercom doorbell (different batches, accessories style and color are random) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.