Wireless Doorbell Intercom 2.4GHz Mini Portable Dual Way Voice Intercom Doorbell Interphone System Built-in Microphone and Speaker, Ultra-Long Standby

Description: This is a portable doorbell system for home, factory, hotel, market, and more. Built-in microphone and speaker allow super sound quality for dual way communication. Simple and small design, easy to use. Specifications: Indoor Bell Outdoor Bell Power Supply Rechargeable Lithium Battery 4 x AAA Batteries (NOT Included.) Input Interface Micro USB               Wireless Frequency 467.6375MHz Transmission Distance 300m 5 ~ 50m Working Time > 6 Months 48h Working Temperature -20 ~ 55 Size Approx. 100 * 60 * 16mm / 3.9 * 2.4 * 0.6in Approx. 100 * 60 * 16mm / 3.9 * 2.4 * 0.6in Package Size Approx. 170 * 120 * 25mm / 6.7 * 4.7 * 1.0in Package Weight 150g Package List: 1 * Indoor Bell 1 * Outdoor Bell 1 * USB Cable 1 * Screw Driver 1 * User Manual