This is a lid to house the switch and harness for my low extruder temp mod for the UP printer.I've used a 13ohm resistor inline with the termperature probe, to trick the printer into thinking the temperature is higher than it actually is. I found 13 ohms drops the extruder temp to around 240 C. ( I found this a good compromise for most colours) Although it still shows 270 in software. The addition of a switch allows quick and easy changes from OEM to aftermarket filament. The plugs are JST-XT. Update - I now recommend using a 10 ohm 1 watt resistor as the 13 ohm can drop the temperature a little too far when printing with Taulmans nylon. The 10 ohm will give around 250-255 C. I also now offer the patch lead for those who don't want to, or can't make their own. http://www.3dprintergear.com.au/UP_low_temp_filament_mod_p/templead.htm