Use these Lazer Tripwires to make an invisible fence around your precious valuables. Each unit has a sender and receiver and if any of the beams are broken the alarm will sound. Use the bottle of “special laser water” to mist the beams and align them. You can add as many units as you like to extend the fence. The lasers are eye-safe LEDs and each unit needs 2 AAA batteries. US$42.49 for a pack of three from Amazon.
In the old days, keeping unwanted nosy brothers and sisters out of one’s room meant hanging a crudely lettered sign that read “KEEP OUT”. Today, these matters are a lot more high-tech, as is evidenced by this “lazer” tripwire system. It features three units to be planted at strategic positions around the area one wants to protect. Each unit is capable of emitting a safe LED beam and sense other beams being received, this establishing a perimeter.