The heatsinks are cooled with 92x25mm fans that are attached on a removable plastic stand:

BTF80/90 models use the same fan with PWM (Pulse-Width Modulation) rotation speed control option. So, the fan rotation speed is automatically adjusted in the interval between 750 and 2,500RPM (±10%) with the maximum level of noise at 27dBA and 42.8CFM airflow. BTF92 O.E. cooler got this “O.E. - Overclocker Edition” addition to its name not only due to larger size but also to the use of an advanced fan (as the manufacturer claims). Its rotation speed can be adjusted from 1,000 to 2,300RPM (±10%) thanks to the rotation speed controller bundled with the cooler. In reality the maximum fan rotation speed is much higher than the 2,300RPM claimed in the specifications. The fan can speed up to ~3,060RPM.

The base of both coolers is covered with transparent plastic film to protect the copper surface against scratches and other unpleasant incidents:

And there is a lot to protect here, believe me. The base is impeccably even and features remarkable mirror-shining polish:

Now I have to say a few words about the heatpipes in the heatsink base. First of all, they are arranged not linearly but alternate in pairs to ensure better distribution of the heat flow over the heatsink plate array:

Secondly, each cooler has four heatpipes, as you remember, but each heatpipes originates from the base and then returns to the same base after looping through the heatsink array:

In other words, the copper plate in the cooler base contacts eight heatpipes at once, which we haven’t ever seen before (the maximum number of heatpipes in the base we saw was 6). Here I would also like to add that each heatpipes sits in a special groove. Each heatpipe is soldered to the base. I also have to stress that the cooler is put together in a very high-quality way, features very reliable design and secure contacts between its elements.