CPU heatsinks that I turned into lasers. These are the CPU heatsinks I use for pretty much every desktop build I do.
I love these things. I use a drill press to bore the hole for the aixiz module. The heatsinks alone are enough for no duty cycle but if I wan't I can also use the fans that come with them and hook them back on. I've run 445's at 1,800mA for over an hour 1/2 without any problem at all.