This is a set of clams to support the Minitronics controller board produced by RepRapWorld, together with its accompanying fan. The authors of the board have also designed a thingy to attach the fan to the board http://www.thingiverse.com/thing:85977, but well, it was not what I was looking for. This design will allow you to independently attach the Minitronics board and the cooling fan to the rods of your RepRap, provided the frame is made of 6 mm rods.