Instruct: Classify the given review as either positive or negative.
Query: Total waste of money

These blacklights are far too close to the visible light spectrum to be of any use at all. In addition, they are so dim you have to hold them <1" from the surface you are trying to inspect. If you are looking for a portable blacklight, go with a flashlight with no higher than 385Nm. These must be 400+. I purchased three and needless to say, I will not be using any of them.