Motion Sensor BASE, Suitable for SONOFF SNZB-03 and SONOFF PIR3.
With the universal joint, the sensor can be flexible to rotate a full 360°horizontal angle and 90°vertical angle which allows you to adjust the sensor into an optimal angle to view everything in your home (The sensor doesn’t move on its own based on your motion). Another convenience for your home is that you can use the sensor for a position where the movement is not easy to be detected via mounting it in the universal joint, and just rotate the universal joint head to get a wonderful detecting angle.
Note: SONOFF DW2 doesn’t come with batteries into the package.
SONOFF DW2-RF - 433MHZ RF Wireless Door/Window Sensor 
Waterproof DS18B20 Temperature Sensor Temperature Transmitter 1m 