I didn't like the six-way header pin connector used for the hotends. I found the pins would keep sliding back through the plastic, so instead I decided to switch to using 9-pin D-type connectors. This part attaches a connector just below the extruder so the entire hotend connection (bowden tube and electrical wiring) is connected in once place - at the extruder.Print out three copies. Attach a D-type connector using two M3 bolts and nuts. Attach to the extruder using the existing M3 bolts either side of the bowden tube hole. I used the following pinout: Pin 1 - Thermistor Pin 2 - Thermistor Pin 3 - no connection Pin 4 - Fan +12V Pin 5 - Fan GND Pins 6/7 - Heater cartridge Pins 8/9 - Heater cartridge Or you could use a 15-pin VGA connector for more signals such as for cooling fans.