It is entirely passively cooled. The GTX 950 has a thermal profile (TDP of 90W [0]. The 350W recommendation is for your entire system, it's not asking you to add 350W to the size of your current power supply. The Airtop can passively cool about 200W, so they put in a GPU at 90W TDP, and a CPU at 85W TDP
Awesome. I bought a NoFan from quietpc.com last year but I struggled to get a completely fanless setup capable of driving 4K at 60Hz (there was exactly one fanless card they offered which had displayPort 1.2).... Now though it looks like Airtop will be my next upgrade!
An ordinary GPU can be made fanless with an aftermarket cooler. The Arctic Accelero S3 will handle 135w TDP cards without a fan. That's sufficient to cool a GTX 1060. You will need a large case with plenty of ventilation.
My next system is going to be an Airtop as well! I'll be in the market at the beginning of next year, so I'm hoping that they'll have a new model by then with the 1050 or 1060, and that they'll get one of the newer processors that packs more performance per watt.
[0] http://www.anandtech.com/show/9547/nvidia-launches-geforce-g...