Pair of RepRap Thermistors #1 EPCOS B57560G104F, Prusa Mendel

Note that these are much larger than the thermistors that come with the J-head on the NWREPRAP kit. You will have to drill out the thermistor hole in the extruder head and change the firmware to have thermistor #6 not #1. Frankly these are better and more robust than the smaller ones. Also they come with the little heat resistant tubing for the leads.

Worse than useless because they worked just enough to get me to try other solutions for my printing problems. Because of the relative complexity of 3d printing, I have experienced a mountain of frustration, wasted filament, one trashed e3d hot end (broken drill bit inside the heat sink due to clog from way inaccurate temp readings), a lot time and, ultimately, money out of my pocket. To say I am extremely dissatisfied would be an understatement. I should have read the reviews, and believed them, before purchasing this product. One word: don't.

Only needed 1 thermistor so far, and its working great!