Brand New WS4975W Vanishing Wireless Door Window Sensor, EU European Version  Only works in Europe
Who wants something bulky, unsightly and difficult to install?
Most Windows Sensors are hardwired and require either costly professional installations or a frustrating trial-and-error process. Not so with DSC's Vanishing Wireless Door Window Sensor
, as its wireless capabilities allow the unit to simply be mounted within your chosen door or window frame using the supplied double strick tape or screws, sending an entirely wireless signal to the receiver of your choice when an intruder attempts to make an unannounced visit.
This is simply the thinnest window sensor on the market today and can be concealed easily within any window or door frame of any size, which means that intruders will not only be easily detected, but they'll never see it coming. The WS4975W 
uses a replaceable lithium battery and should last 5 years under normal usage. Features:

Revolutionary Size (Virtually Disappears)

Lithium Battery

Perfect for Vinyl Windows

Rare Earth Magnet

Fully Supervised

Frequency 433.92 Operation Temperature -10C-+50C Normal Battery Life 5 Years Varies with Usage and temperature Battery Type Panasonic CR2032

Returns accepted for this item if it's within 30 Days