Heatsink Top:
Two stainless steel socket 478 retention clips hold the large Jet 4 heatsink in place by clamping down on the aluminum fan shroud at either side of the cooler. The remainder of the Jet 4 is constructed from thin sheets of copper soldered to a 4mm thick copper base.

Side A:
This looks like the exhaust end of the fan the way it is designed, but is actually another air intake. The build quality of this heatsink is evident through the nice tight joints at the corner of the shroud which is swaged firmly into the copper base. The aluminum shroud has some vents punched into it to allow air to escape along the outer row of copper fins.

Side B:
The jet engine styled fan is larger than the rest of the heatsink, so if you are looking to use this cooler in your computer, make sure there is enough vertical room to accommodate the roughly 135mm height. The copper base is 4mm thick, and the copper fins measure 0.3mm thick. Each of the 44 fins measure 29mm tall, and are spaced 1mm apart.

The base finish of the copper plate is pretty good, of average flatness, with a typical sanded finish of approximately 32microinches roughness. The copper base is 60x66mm in size, so if you ever wanted to try a little modified TEC cooling here, that could work rather well.