It DOES work on 3-pronged (grounded) plugs, and everywhere, July 24, 2010

I've used this adaptor to run my laptop in China, France, Italy, England, and Ireland. Although it's made of plastic and feels a little fragile, it's really quite hardy and it's worked like a charm in every location. I've purchased several as gifts and always been treated as a hero afterwards.One popular (and funny) one-star review on here claims that the adaptor doesn't work with grounded plugs. That's 100% wrong. It works with them in a hotel, it works with them in a motel. It worked with them in France, and when I used it to iron my pants. (Well to plug in my iron, anyway.) I've never used it on a boat, but it helped my computer write a note.Okay so I'm not as funny as he is. But this thing really works.