Try it out be for you buy no refund. Intruder /Burglar Alarm system sounds. When an intruder comes into your room, home or office and steps on the hidden Transparent Alarm they set of the alarm! It is loud and clear. DVD quality sounds of a very very LOUD Alarm sound. This one has the diagram of the trigger able standing spots for ease of installation. Many people have public rooms but don't want people 'playing around' when they are not there! THIS is the solution. Place two to three of these around in the room, it is guaranteed to run them off! This version with the Transparent Alarm not showing the landing spots can be installed in most rooms. Get is close to where you want it with the furniture move tool. Now, Press and HOLD the SHIFT Key. Notice the 4 arrows change to 3 arrows? Pull down very slowly with the mouse and 'sink' the Guide Carpet down. :D Sink it until it is just under your carpet. NOW - It is Triggered and ready. Please Note! (: I am not responsible for anyone having hearing damage from this product! :) (: IT IS LOUD :) If your ears start bleeding, please seek medical help as soon as possible :D