Those are an almost exact replica of the Ess turbofans, some reviews that compare the real and the replica are available on the internet, knowing that the real ones come at a price of 185euros. The quality is the quality you get for 30$, not very good, but ok, the lens seems tough enough, and the fan works though I had to do a bit of soldering to inverse the polarity of it, so that instead of blowing air in the goggles, it sucks it out, which is how it's supposed to be. I haven't tried the goggles in combat situations now, so I can't tell if the fan is effective or not, and if I still get fog. The noise made at the first speed is low, but the second speed is very noisy, I guess it's supposed to be used for a few seconds if it starts to fog.
One bad thing is the way the battery holder is attached to the headband, and the way the headband is designed : if you have to tighten the strap, it's just a pain (only a photo would be effective to describe it), so I had to unpick the strap in some places to arrange it myself.
Overall it seeams like a good product for the price I paid.