This is a modular cooling system for the MakerFarm Prusa i3. It uses 2 40mm fans (accepts both 40x40x10 and 40x40x20), one to cool the filament as it comes out of the nozzle, and one to cool the fins of the hot end. It was initially designed for a Metal Magma hot end, but it may also work with a J-Head MK-V hot end since it is only a few mm shorter than a Metal Magma. I have also included a modified fan shroud and cooling duct to work with the J-Head MK-IV hot end.If you are using this for a MetalMagma hot end or a J-Head MK-V, download and print the parts that start with "Magma." If you are using this with a J-Head MK-IV, download and print the Magma_Hot_End_Cooler_Mount.STL, Magma_Hot_End_Cooler_Revised.STL, Fan_Shroud_Left.STL, and the Filament_Cooler.STL. The Fan_Shroud_Left.STL and Filament_Cooler.STL accommodate the taller height of the J-Head MK-IV. Fans attach with #4 machine screws. Mounts attach to cooling ducts w/ #6 machine screws.