I picked one of these up on a whim off eBay the other day.
It's a cheap piece of equipment shipped straight from China, made by a company called Resun.
I've gotta say, even though I'm only a day into using it, I'm pretty darn impressed.
It's a corona discharge unit, will run on 110v or 220v with no adapter necessary, has a variable output between 50 and 250mg/hr and a built in air pump. Even when the generator/pump isn't running, it allows enough air through to allow my APF600 to keep skimming just fine. It's fairly compact, quiet and seems well built. I can't speak to it's longevity, but again, I'm very impressed, especialy once you consider I paid a whopping $42 for it
I thought I'd throw up a quick review in case anyone was interested.
A friend of mine is currently using several Resun products and has been impressed. Search for Resun on eBay and check out the stuff they make. Nice gear, dirt cheap.