Feature:1. Dual Way Intercom: When someone press the call button on outdoor unit, the indoor bell will ring immediately for reminding you. You can press the response button to talk with the people outside.2. Waterproof Design: The intercom doorbell is waterproof even in bad weather conditions like snow and rainstorms. Features low power consumption, built in 1800mAh battery, and included 2 base.3. Easy to Operate: The surface of the doorbells adopt high gloss UV process, and the keys feel good. Intelligent humanized design, with intercom light and power light display, customers can see at a glance. No need to network without wiring to turn on and use.4. Low Power Consumption: Wireless voice intercom doorbells adopt intelligent power saving chips, they can be used for more than six months under normal conditions after being fully charged. When they do not work normally and never consume electricity.5. Multiple Use: Wireless doorbells are equipped with two indoor doorbells that can switch between ringtone call mode and walkie talkie mode when used as walkie talkies.Specification:Item Type: 2 Way Voice Intercom DoorbellMaterial: ABSModel: H8Battery (single external battery): Rechargeable lithium battery 3.7V 1800mAh (with built in battery)Use: Widely used in household, office, laboratory environment, medical treatment, etcBasic Parameters:Working Temperature: -20℃ to 55℃Transmission Distance: 1000 meters in open space. Partition wall 20 to 50 metersWorking Frequency: 410M to 490M.Package List:2 x Voice Intercom Doorbells2 x USB Cables2 x Bases1 x Instruction Manual