Features: 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 Doorbells_x000D_ Material: ABS_x000D_ Door Machine: 2000mAh 103450 lithium polymer battery (built in)_x000D_ Indoor Unit: 2000mAh 103450 polymer lithium battery (built in)_x000D_ Working Temperature: -20-55_x000D_ Transmission Distance: About 1000 meters empty_x000D_ Working Frequency: B gear frequency 462MHz, A gear frequency 434MHz_x000D_ Charging Time: About 5 hours to fully charge_x000D_ Music Ringtones: Optional_x000D_ Ringtone Volume: 3 gear adjust (standby to adjust the volume key)_x000D_ Call Sound: 3 gear adjust (call working time adjustment volume keys) PackageList: 1 x Transmitter 1 x Receiver 1 x Charging Base 1 x Charging Cable 1 x Screwdriver 1 x Instruction Manual 1 x Double Sided Adhesive 1 x Adapter Cable