The heatsink looks like two regular heatsinks glued together, it's really quite bizarre, but at the same time it looks very manly with it's twin fan pointing into the center of the heatsink. The heatsink is made out of aluminum and a nice 4mm thick copper base, machine lapped to perfection. Not as good as what we've seen on for example Swiftechs waterblocks, but pretty close.
The Silet Twin seen from above
The 4mm copper base of the heatsink
The retention mechanism is very good, using all six socket lugs to provide a stable and secure way of fixing the heatsink to the socket. Using all six socket lugs should eliminate the possibility of the lugs breaking off during installation or removement of the heatsink. Another really great detail is the notch where you can put a screwdriver when installing the cooler without having to worry about it slipping , leaving you with a huge scratch your precious motherboard. There's also a small tube of Arctic Alumina and a converter that let you use both fans on only one fan header, in case you only have one free. It is small details like this that really make this cooler stand out in the crowd.
Accessories that comes with the heatsink
The retention mechanism, using all socket lugs to provide a secure way of fixing the heatsink to the socket
The dual fans are custom made by the German company Pabst, a very well known manufacturer of fans. Microplex chose a dual fan setup because this gave the best performance/noise ratio compared to a bigger, single fan. Each fan move ~11CFM, ~22CFM in total, with a noise level as low as 19dB. Competing products like Silent Viking and the Silverado has a noise level in between 20dB and 25dB.
In addition, you get extra security in case of a fan failure -- should one fan fail, the other will still spin, and thus give you the time to power down your system before the CPU is getting really hot.