Feature:1. Wide Application: Wireless intercom doorbells is widely used in homes, hotels, villas, factories, hospitals, etc.2. Wireless Distance: The barrier free distance of wireless voice intercom doorbells is about 1,000 meters, which requires no internet, no wiring, and can be turned on and used.3. Intelligent Design: Voice intercom doorbells adopt intelligent and humanized design, with intercom light and power light display, and the operation is clear at a glance.4. Working Time: The outdoor unit and the indoor unit both use 2000mAh batteries, and the outdoor doorbells work normally. It can work for about 8 months by pressing 5 times a day and talking for 2 minutes at a time, and the indoor doorbells work for about 1 week.5. Excellent Chip: Wireless voice intercom doorbells adopt a special intelligent intercom chip with strong penetrating power , which can be used from the 1st floor to the 8th floor.Specification:Item Type: Wireless Intercom DoorbellsMaterial: ABSUses:Used in Homes, Hotels, Villas, Factories and Hospitals.Outdoor Doorbell:Type of Battery:2 x Rechargeable Lithium Battery 2000mah(built in)Working Temperature: -20℃-55℃Wireless Distance: 1000m (Barrier Free) /20-50m (Barrier)Wireless Frequency: 410-490mhzWorking Hours: More Than 8 MonthsWaterproof Grade: IP54Product Size:Approx. 121.5 x 61.5 x 313.mm / 4.8 x 2.4 x 1.2inIndoor Doorbell:Working Hours: About One Week.Waterproof Grade: N/ASize:Approx. 125 x 70 x 56mm / 4.9 x 2.8 x 2.2in.Package List:1 x Outdoor Machine1 x Indoor Machine1 x Charging Base2 x USB Cable1 x Screwdriver1 x User ManualNote:1.Indoor and outdoor units are shipped with built in batteries.2.Do not place the product in an environment with excessive corrosion, humidity and high temperature.