This is a product that will definitely not be useful for everyone. If, however, you’re a mechanic, building inspector or anything like that, you will from now on want to carry this with you all the time.

In several professions, it’s often desirable to see what’s going on in dark nooks and crannies. One option would be to train a ferret to do your job for you, but more commonly, inspecting these spaces means taking everything apart.

This is where a borescope can make life much easier. With a camera head only 0.22″ (5.5mm) in diameter and a 11½ feet (3.5m) flexible cable, you can snake this device through pipes, behind walls, or deep into machinery’s innards. Integrated LED lights’ brightness can be adjusted for a better view.

Here’s a short video of a plumber using it on the job:

Unlike regular monitoring systems and professional borescopes (which can cost ten times as much as this one), the Depstech does not come with a screen. Instead, you use this gadget with your phone and connect through wi-fi.

The good news is that both Android and Apple’s iOS are supported. The bad news is that the necessary software can be tricky, and several people have complained that the “waterproof” camera really just isn’t.

Still, the fact that this can be used with your existing phone and its extremely low price earns this device a spot on our list.