Yes- they do. Here's the identical item, different name.
http://www.livingincomfort.com/12volminwren.html
Recommended.

Jim C
On Nov 2, 2008, at 11:36 AM, Courtney Hook wrote:

> Jim, do those things have any REAL power? I've always been really
> sceptical about them, I bought a 120volt one instead, which really
> does work. What brand/model did you buy? I might pick one up then,
> if it really does work?
> Courtney