While the Thermalright HR-03 series are certainly great VGA coolers, they are also quite large and take up a good bit of space. Depending on the size of your CPU cooler, other motherboard components and how much space there is in your PC case, you may run into interference issues using the HR-03, especially in SLI or Crossfire. So in response to this Thermalright developed the T-Rad² specifically aimed at supporting multi-card configurations. With its slim 25mm height the T-Rad² offers the same nickel-plated copper heatpipe and aluminum fin cooling as the HR-03 series, but in a much thinner package. The T-Rad² GTX continues support for nVidia 8800/9800 and ATI 3800/4800 cards while adding the nVidia GT200 55nm core cards to the compatibility list.

http://www.ocia.net/reviews/trtradgtx/page1.shtml