Smart Call Doorbell with Loud Voice, Clear Intercom 1 with 1 Wireless Voice Intercom Doorbell               The indoor unit and outdoor unit are wirelessly connected at a long distance without wiring. The open distance can be up to 200 meters, and the obstacle distance is 20-50 meters.  Two-way intercom, wireless distance 200m.  The loudspeaker is loud, the volume is adjustable, and the ringtone is changed, the intercom sound quality is clear, and it can be used for mobile intercom.  Scope of application: residential buildings, factories, hotels, hospitals, tea houses, shops, and places in Ligong.  Working frequency: 467.6375MHZ    Working temperature: -20--55 degrees Celsius  Working frequency: 467.6375MHZ (no waterproof function)  Power supply voltage 1.5 (V)  Power supply mode External machine: 4 AAA batteries + internal machine: USB cable power supply (without battery)  The outdoor machine has a long working time, 4 batteries can reach more than half a year  Product weight: 105g  Scope of application: residential buildings, factories, hotels, hospitals, tea houses, shops, and public places  Colour: black  Material: ABS  Size: 10x6x1.3cm    Package Contents:  1 * Doorbell  1 * Receiver