Features: Wireless intercom system, no telephone wires needed, save your phone bills. Clear Voice and Secure Digital Communication. 433MHz working frequency, anti-interference signal. It needs no installation nor an installer, simply plug and use. Built-in rechargeable battery, works with or without electricity power, standby time 30 days. Long communication distance up to 500m(depending on the environment). Can be placed on desk or mounted on any surface, horizontally on wall surface or vertically on any flat surface. A wireless intercom system can be a convenient way to communicate throughout your house, office or warehouse. This Plug & Play Wireless Intercom is very simple to use, clear two way communication and has an impressive 100 meters within building and 500 meters in the open field without barrier transmission. Specification: Standby Current: 800μA Working Current: 400mA Charging Current: 230mA Working Frequency: 433MHz Transmission Rate: 256K Power Supply: DC 5V Removable Battery : 3.7V 18650 Size: Approx. 217 x 112 x 70mm/8.5 x 4.4 x 2.8inch Application: Widely used in homes, offices, warehouses, workshops Operating Instructions: 1. Simply plug and play 2. The intercoms ID code had been set. the ID code is listed on the top right corner of intercom. 3. Full charged the intercom to power socket directly, turn on switch at the bottom. 4. Dial the ID number(1, 2, 3) for which you want to call and press call button, the called intercom will rings, pick up and answer the call. Package list: 1 x Wireless Walkie Talkie 1 x Data Cable 1 x User Manual . Note: Please note that the new type and old type of this product will be sent randomly, and make sure you will not mind before ordering.