Features Motion sensor: Wireless welcome doorbell alarm that detects motion and sends signals to the receiver using a sensor, with the option to select at least one transmitter. MULTIPLE RINGS The receiver features a doorbell design with 22 different ringtones for individual preferences and 8 doorbells for retail use. WIRELESS DISTANCE This wireless doorbell can be transmitted from a long distance, with an open space of up to 280 meters, suitable for larger locations or higher floors. Multiple functions: motion activated sensor ringtone, door alarm, email notification and additional quiet, strong vibration reminder, which is suitable for private or quiet places. Applicable places: this motion sensor doorbell is suitable for shopping malls, office spaces, factories, hotels, high-end clubs, houses, villas, etc., simple and practical. Specification: Item Type:Wireless Doorbell Model: KS SF20R. Receiver battery: 3 x 3V AA alkaline battery (not included) Infrared detector battery: 3 x 3V AAA alkaline battery (not included). Power supply: 5V Micro USB Volume: 80-96dB power supply Transmission reception frequency: 433.92 MHz Wireless range: approx. 280 m outdoors. Ambient Temperature: Receiving Host: -10-60℃; Infrared Detector: -10~33℃ Ambient humidity: < 80% RH. Storage Temperature: -20-70°C Package list: 1 x receiver. 1 x infrared detector. 1 x holder. 1 x user manual (English language not guaranteed). 2 x screws. 2 x plastic plugs. 1 x double-sided tape Package List 1 x Receiver 1 x Infrared Detector 1 x Bracket 1 x User Manual 2 x Screws 2 x Plastic Plugs 1 x Double Sided Tape