Features: 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 Doorbells Material: ABS Uses: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: 410-490mhz Working Hours: More Than 8 Months Waterproof Grade: IP54 Product Size:Approx. 121.5 x 61.5 x 313.mm / 4.8 x 2.4 x 1.2in Indoor Doorbell: Working Hours: About One Week. Waterproof Grade: N/A Size:Approx. 125 x 70 x 56mm / 4.9 x 2.8 x 2.2in PackageList: 1 x Outdoor Machine 1 x Indoor Machine 1 x Charging Base 2 x USB Cable 1 x Screwdriver 1 x User Manual Note: 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.