BroadLink Door Sensor (SR4D) - White Spec:

Brand	BroadLink
Power Input	Dc 2.7-3V (2x AAA Batteries)
Communication	Bluetooth 4.0 and above
Working Temperature	-10°C~ 45°C
Working Humidity	<85%RH
Supported OS	iOS11/Android 5.1 and above
Model	(SR4D)
Color	White
Warranty	12 Months

Overview For BroadLink Door Sensor (SR4D) - White 

Do you want to live in a smart home where security and comfort come first? Introducing the "Broadlink BLE SR4D Door Sensor" - your first step towards smart home control. This innovative product is designed to provide peace of mind and convenience without compromising the aesthetics of your home.
With Broadlink BLE SR4D , you will receive instant notifications on your mobile device for any unauthorized access attempt. It is easy to install and does not require additional wiring, making it ideal for busy people who value their time and convenience. Its compatibility with other devices in the Broadlink BLE series allows integration into a wide range of home automation scenarios.
Protect your home and improve your quality of life with one click by browsing more products from the Broadlink BLE BroadLink series . Suitable for families who want to live in a modern and secure environment, as well as for individuals looking for smart solutions for their home comfort.
Broadlink BLE SR4D Door Sensor - is the ideal option for controlling your Broadlink BLE lighting or scenes when a door or window is opened. 

Can be placed anywhere