Is this someone's attempt at marketing SDR to the masses? This is nothing new, and I'm surprised to see how little information they put forward about it.
It's just a low power FM station with a raspberry pi in it as a controller. It would be highly illegal to use this device in most modern nations without a license.
higher power. The n900's transmitter was 15nW (1.5e-8 W), which is why it was legal. For a claimed 6km radius, I would assume this is about 3-7W output.