Here is the heatsink I'm using right now. http://www.dealsonic.com/thera1ddrsdr.html . It works but does not fit that well. I've got the two heat sinks side by side runing long ways on the quark controller. They are not quite long enough and a little wide. I might order one more set and run them the other direction and cut the extra off. That way it would be a cleaner fit.