This is a clip-on ducted fan that is modified to fit with a Makerbot Replicator Dual (or 2x) with Carl's AluCarriage Dual and Alu-Dual Cooling Block. The source OpenScad and STL files can be found at this Github repo. Please feel free to make fixes, issues and submit pull requests. Print the three STL files (two fan ducts and the spacers). Then reverse the direction of your fans by turning them around and replace the OEM spacers with the printed ones. The fan ducts will then slide over the fans and direct air over your printed objects. Carl Raffle's carriage and block upgrades require M3x55 mm socket head cap screws and printed spacers for the motor found here.