Nothing special - looks like a cheap version of a PowerDive -
www.powerdive.com/product/powersnorkel , although doesn't look as though it has the air reservoir/accumulator tank .
I wasn't convinced about the value in having the compressor floating so I went for the non-floating double version as seen here:
www.powerdive.com/product/double-deck-snorkel . Sits in the cockpit when needed, runs from the boat batteries, and gets a lot of use.
None of the hookah units are a substitute for a proper diving course.
