That's the Dymax Vortex Fan. It comes in two model W-8 and W-5 good for small tank but can be quite noisy. I had one for a IQ5 and it works well and looks good. I think everyone appreciates better info rather than just plain talk. Here's more info
http://good2bcheap.files.wordpress.com/2010/11/p1170449x.jpg
http://good2bcheap.files.wordpress.com/2010/11/p1170445x.jpg