I liked the simple design of the OB1.4 Dual E3D extruder from downeym, so I remixed it to fit on the RepRapPro Mendel carriage. It replaces the complete front nozzel mount of the carriage, so its easy to swap it with the original. I placed also two holes in the mounting cap to mount a 50mm fan. I have updated the design for better airflow through the cold end to the sides and not so much to the hot end. There is now also a possibility to mount PLA fan ducts on the side. I added a much simpler version of the carriage. It should work also with the newer E3D-V6 hot-end and its new embedded bowden coupling (not tested, because I haven't one).