After trying several variations of the RostockMAX hot-end fan ducts/shrouds available on Thingiverse I was left unsatisfied. http://www.thingiverse.com/thing:43983 came close to what I wanted, but as I apparently have SeeMeCNC's v2 nozzle it didn't fit. I spent a good deal of time learning new surface modeling techniques in ProE so that I could design this duct. It has a very simple mount that grasps the aluminum stand-off in the corner of the stock SeeMeCNC effector and uses a single screw through the unused hole to secure it in place. There shouldn't be any interferences on a stock setup. While it looks quite close to the hot-end, I ran these ducts for nearly 100 hours of printing and noticed no heat-induced deformation of the duct. I found that a single duct improved print performance (I use ABS, but I'm sure it will help PLA as well) satisfactorily, but I printed two because I had two 40mm fans. I wouldn't say it doubled the cooling performance, but it was better. I would imagine that a third would again be helpful, but I would also begin worrying about the additional weight on the effector. As it usually goes, I have even further modified my MAX to use magnetic (ball-joint) arms and these ducts are now desk decorations. The new effector and cooling design is soon to come...Print both parts. I don't remember my exact print settings, but I think I used 3 perimeters on the mount with 60% infill and 1 perimeter on the duct. Both were printed at 0.2mm layer height with a 0.5mm nozzle. I used M3 screws, but #6 would work just as well (they differ by 0.0015 in). On the duct I ran an M3 plug tap through the four fan mounting holes and an M3 bottoming tap in the duct-to-mount holes on the side to prevent over stressing the plastic during assembly and avoid any cracking or splitting. I would also recommend a very thin piece of neoprene or other light-weight foam rubber as a vibration-absorbing gasket between the fan to be mounted and the duct. Steppers, especially those that are using any form of micro-stepping, are very sensitive to vibrations and if your fans are not well balanced, you might introduce a source of missed steps.