The 120mm PWM fan on Glacialtech's F101 PWM heatsink rotates at 1700RPM by default, as slow as 800RPM when the computer is idle. Power is supplied by a 4-pin PWM motherboard fan header. The F101 PWM heatsink stands 145mm tall, is 143mm at its widest. The extension adds about 35mm the width of the heatsink, but at a height to allow clearance over typically sized chipset thermal solutions on the motherboard.

Clearance below the 35mm wide fin extension (to the right) is 66mm to the CPU. From the back you can clearly see Glacialtech have left mounting points for a second 120mm fan to be installed. Though the second fan is not supplied, Glacialtech do include extra clips to hold one in place.

Each aluminum fin on the F101 PWM heatsink is 0.3mm thick and spaced 1.5mm apart. There is a 2mm plenum behind the fan. The entire heatsink stands 145mm tall, with 31mm clearance below the lowest fin.

Five 6mm diameter sintered-wick copper heatpipes pass through the aluminum fins. At the base the heatpipes are packed edge-to-edge to ensure good thermal transmission from the 2mm thick copper base plate. The base measures 38x50mm in size. I'd like to know who thought it was a good idea to stamp "GlacialTech.com" there.