NAME: Spy Gear Lazer Tripwire
WHAT DOES IT DO: It uses invisible LED beams projected from three units, so you can form a perimeter. When an intruder breaks the beam, the receiver unit alerts you with an alarm, so you can quickly assess the situation and respond appropriately.
HOW MUCH: $25
FUN FACT: I will mostly use these to prevent people from sneaking up on me in the office.