The CHC-37-L06 is for GeForce 7800/7900GTX voltage regulator circuits. It is a high density copper block with rotational L-nozzles and 21k gold plating inside and out. It replaces the rear "VREG" heat sink of 7800GTX and 7900GTX video cards when liquid cooling the main GPU (which removes the default air flow).
The CHC-37-L06 is not intended for 7800/7900GT cards, ...
Voltage regulators can run especially hot on late model VGA cards (nVidia 480 GTX), upwards of 100-120 degrees C. Thus, Thermalright created a cooling solution to help stabilize VGA overclocking. The VRM-G2 is designed to take advantage of a side panel case fan.