If you're into your electronics and wanting to know power consumption/outputs then this is golden. It measures current and voltage of the power supply via a USB port. The data shows up instantly and it works really well. With this, you can learn everything about your laptop, camera, tv or any other USB device. It also has a USB output so you don't lose a USB port. It arrives in a small plastic pouch and it works perfectly. It feels well made and nothing wiggles or gets hot. It's in a clear case too which is pretty cool. This is super useful for efficiency testing. For instance, we used to to check whether it was our phone or our USB port that was causing charging issues.