If you have a Yale wireless alarm B & Q have reduced the pack of 3 Yale Wireless PIR detectors (HSA3030) from £69.99 to £19.98
I have a Yale wireless alarm (nearly 2 years) and have been very impressed with it - never had a false alarm. Don't know if this can be used with other alarm systems.
Ebayers are selling these saying RRP is £99 but their having a laugh.....
Link to the Yale website belowhttp://www.yalelock.com/Yale/Templates/ProductPage.aspx?id=3314&productid=cc00d6e7-a845-47c9-824f-c0162f6d5fe5
These are instore clearance prices. Can't find them online.