What is inside HUMplug-e

Anyone has experience on this HUMplug-e product ?

Web page

" Simply plug your equipment through this, to cure it of Ground Loops. Filters out unwanted voltage and current in the ground line that cause ground loop hum while simultaneously maintaining a solid, safe ground."

I have experience on many different way on solving ground loop loop problems in audio/vidoe systems. Practically every other types of products listed on that page are known to me in details (I have used similar produicts, know what is inside such items, even manufactured some quite simlar products). I have written some material on ground loop solving to

How this HUMplug-e product works makes me wonder. Given the specifications (15A current) and a small size it can't be an isolation transformer. According the description it keeps the solid ground connection it just can't be a "cheater" plugs that just simply cuts ground connection (dangerous peactice that is not recommended).

My quess that it does some magic on ground connection so that it stops/reduces the current that can flow on normal ground loop case, but still lets the ground connection to be good enough for electrical safely. I am just wondering how this is done in such what that it works and meets the electrical code safey requirements. Anyone has experience on how this is implemented ? Some of my quesses would be those impklementation possibilities:

- some common mode coil type construction over all wires

- two parallel diodes (on different directions) wired between input and output ground connections (stops current when voltage difference is low but will pass hort circuitfualt currents at low voltage drop)

Anyone commenting my quesses how this device works ? Anyone has experience on this ?