NOTE: The door/window sensor is meant for indoor operation and away from sources of water/moisture and other extreme weather conditions.
To install the door/window sensor, choose a location on the door or window frame. The unit is designed to be mounted vertically, where it will produce the best results. Note that wireless devices should not be mounted directly on or near metal framing or other large metallic objects. Large metal objects may weaken the radio signal transmitted.
When you've picked the location, you can mount the door/window sensor in two ways -- you can screw it into placement with the provided hardware (illustration A) , or use the included double-sided adhesive tape (illustration B). Either one will work; if you use the adhesive, be sure to not cover up the switch on the back of the sensor, as shown:
When you've installed both parts of the door window sensor, be sure that they are oriented toward each other correctly. The round, dimpled indentation on the main unit should face the indentation on the smaller unit, as shown below:
The battery in you door/window sensor should last two years of normal operation. When it's time to replace the included CR2 battery, simply push the latch button at the top of the main unit and remove the cover, as shown below. Then remove the old battery and replace it, with the plus (protruding) side of the battery facing up. Replace the cover, and you system is good to go again.