Feature: 1. Long Distance Intercoming: Barrier free long distance call distance supports about 1000 meters, no network or wiring required, easy to use. 2. Long Standby: Built in 2000 mAh battery, long battery life, press 5 times a day, call for 2 minutes, can work for about 8 months, indoor unit work for about 1 week. 3. Humanized: Humanized design, equipped with intercom light and power lamp display, surface pattern convenient for fast communication operation. 4. Button Design: The button adopts plastic and silicone structure, the surface adopts high gloss UV process, 18mm thickness is convenient and comfortable to hold. 5. Convenient: When the indoor unit rings, press the TALK button to directly intercom, equipped with a charging station, and it can be fully charged in five hours. Specification: Item Type: Wireless Intercom DoorbellsMaterial: ABSDoor Machine: 2000mAh 103450 lithium polymer battery (built in) Indoor Unit: 2000mAh 103450 polymer lithium battery (built in) Working Temperature: -20℃-55℃ Transmission Distance: About 1000 meters empty Working Frequency: B gear frequency 462MHz, A gear frequency 434MHz Charging Time: About 5 hours to fully charge Ringtone Volume: 3 gear adjust (standby to adjust the volume key) Call Sound: 3 gear adjust (call working time adjustment volume keys). Package List: 1 x Transmitter1 x Receiver1 x Charging Base1 x Charging Cable1 x Screwdriver1 x Instruction Manual1 x Double Sided Adhesive1 x Adapter Cable