Heatsink Top:
With the upper fan section of the Polargate AL S removed, you get a better feel for how this heatsink operates. Air is exhausted down into the aluminum fins from each of the CAIRdB fans, and the entire fan shroud is held in place with four vibration absorbing rubber posts. The fans do not come in direct contact with the metal of the heatsink, so any vibrations that do occur are most likely absorbed by the rubber. There are two steel pads for the socket clip to press down on when the heatsink is installed in the socket 478 retention frame.

Side A:
From the side, the Polargate AL S is a rather complex assembly of parts. The twin fans sit back to back, but are separated from one another by a clear plastic window, so exhaust air is not co-mingled. The fan assembly sits on the aluminum frame with a couple rubber posts, and at the bottom of the heatsink is hardware which keeps all the parts of the cooler together. Air enters in through the tops of the aluminum fins, and exits at the base to either side. The small 40mm wide aluminum block holds the fins together (much like Zalman's heatsinks), and a steel plate keeps the heatsink centered over the Pentium4 processor.

Side B:
As you can see here, the twin verax fans sit about half their circumference inside the aluminum fins of the Polargate Al S cooler. Air enters each fan perpendicular to the fan blades, though a 60mm side intake, only to be exhausted downwards parallel to the impeller. This is somewhat similar to a squirrel cage fan. Within the stacked aluminum fins is the base of the heatsink, which is shaped somewhat like a rounded out "m" made from aluminum. This internal prisim-like shape helps to direct airflow out to either side of the cooler, and is a tactic many heatsink manufacturers are using these days. The Polargate AL S stands about 110mm tall, so be sure there is sufficient room in your case. Each of the stacked aluminum fins measures 0.5mm thick, and are spaced 1.0mm apart. The aluminum section of the heatsink covers 65mm of the total height.

The aluminum base comes covered in white thermal paste, and measures 40x83mm in size. The surface finish is nicely machined, and very flat. Because of the internal structure of the base within the fins, the warm exhaust air is directed out and away from the processor itself. Note the steel support strip on each side of the heatsink for the clips to lock onto. The Polargate AL S weighs 425 grams, so it should not pose much of a problem with regards to PCB warpage.