From the web, a list of sensor types : Zirconia 'thimble' type Element type - zirconium dioxide, thimble Types available - one, two, three and four wire, 18mm thread Heater resistance - (3 and 4 wire sensors only) 2 to 6.5 ohms Output signal - oscillating 0.1 and 0.9 volts Zirconia thick film type E...