Feature: 1. Simple Installation: Wireless intelligent intercom doorbell, ultra long distance transmission, excellent signal through the wall, without wiring. 2. 1500m Long Range: With professional interphone chip, the theoretical communication distance in a flat and open place can reach 1500M, making your contact more convenient. 3. Multipurpose: Not only used as an intercom doorbell, but also as a daily interphone and an office pager. It can be used in a variety of scenarios. 4. Anti Interference: This doorbell doubles as a wireless interphone and will not be affected by WiFi interruption! It will not interfere with other smart devices. 5. Wide Application: The waterproof doorbell has a built in low power lithium battery, which can last a long time. It is suitable for home, other fields, companies, teahouses, offices, home stays and other areas. Specification: Item Type: Wireless Intercom Doorbell Material: ABS Battery Type: Lithium Battery (Included). Package List: 1 x Door Bell Internal Unit 1 x Door Bell External Unit1 x Charger Plug1 x Usb Cable