So, well, he seems to be able to test cables, which he is supposed to. So far I could not install still undergoing a field test, but with me rumliegenden cable seem to be OK. But the processing of the device is really the last, the "pocket" is quite dirty and smelly Chemicals therefore, the device itself looks like pulled out a dusty pile of electronic waste. The plastic parts are processed very inexact. The on / off switch can not help yourself, so I have to always open the now almost broken battery cover and disconnect the not supplied 9V manually.
For the price you can expect nothing better of course, I have a rewiring my house before, wenns it reaches heck me be right. But who intends to test more than 5 cable, you should look more like what gescheitem.