Feature: 1. Wide Wireless Distance: Wireless doorbell can up to 1000 meters of barrier free distance or 20 to 50 meters of through the wall distance to meet the needs of many scenarios. 2. Waterproof Design: Wireless intercom doorbell adopts waterproof design, which can be used safely and durably in different seasons and weather. 3. Long Battery Life: The smart wireless doorbell can work for up to 8 months (outdoor) or 1 week (indoor) using the built in 2000mAh lithium ion battery. 4. Two Way Talk: This doorbell supports two way talk for easy visitor access, thus you know who is visiting your house and talk to them conveniently. 5. Clear Sound: Includes 1 outdoor doorbell and 1 indoor doorbell, providing wireless large range calls with stable transmission signal for clear sound. Specification: Item Type: Wireless Doorbell Material: ABS Wireless Distance: Approx. 1000m/1094yd (Barrier Free), Approx. 20-50m / 65.6-164ft (Through the Wall) Operating Frequency: 410M-490M Battery Type: Built in 2 x 2000mAh Lithium Ion Battery (Indoor Doorbell with Outdoor Doorbell) Working Time: Outdoor Doorbell About 8 Months, Indoor Doorbell About 1 Week Sound Adjustment: 3 Gears Adjustment. Package List: 1 x Outdoor Doorbell1 x Indoor Doorbell1 x Sticker1 x Charging Base1 x Type C Power Cord1 x Round Hole DC Power Cord 1 x Screwdriver1 x Instruction Manual Note: Manual measurement, please allow some errors.