This is an enclosure for the Sanguinololu electronics with vertical connectors. It integrates a 40 mm fan and includes ventilation. It uses clamps to attach to an 8 mm rod, so it can be placed anywhere on a Prusa-type 3D printer. You can see the printer I used this for at http://stirlingengine.com/product/reprap-prusa-mendel-3d-printer/ where it is for sale.This is a gift to the RepRap community from the American Stirling Company http://www.stirlingengine.com/The holes for the Sanguinololu are sized so that M3 or 6-32 bolts will self-thread into them. Use 10mm or 3/8" long bolts for the two holes that will not be using the mounting clamps, and use 20mm or 1" long bolts for the holes that will be used with the mounting clamps.The mounting clamps are sized for 6-32 nuts. If you are using metric, one of the Prusa endstop holders can be substituted and will work equally well.