Adjustable speaker for clear sound and mobile intercom functionality. Energy-saving design with long standby time. Wireless transmission range up to 300 meters in open areas. Simple and convenient installation with included double-sided tape. Operating temperature range of -20 degree Celsius to 55 degree Celsius for versatile climate suitability. Item Name: Wireless Door Bell Material: ABS Features: Versatile, Convenient, Durable, Decoration, Fine Workmanship, Long-lasting Operating Temperature: -20 Degree Celsius to 55 Degree Celsius Wireless Distance: Up to 300 Meters Without Any Obstacles (50-100 Meters with Obstacles) Frequency: 467.6375MHZ Power Requirements: Indoor Chime Uses Rechargeable Battery; Outdoor Chime Uses 4 1.5V AAA Batteries (Not Included) IP Rating: Not Applicable Size Details: L: 10cm/3.94", W: 6cm/2.36", H: 1.48cm/0.58" (Approx.) Notes: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 x Indoor Doorbell 1 x Outdoor Doorbell (Without Battery) 1 x USB Cable 1 x Screwdriver 2 x Double-sided Adhesive 1 x User Manual