Standard T-type Thermocouple Wire with PFA insulation This is a T-type thermocouple wire with blue Teflon PFA insulation, which is good up to about 260 C or 500 F. This T-type thermocouple wire can be used to make your own thermocouples for a wide range of applications, or to make your own extension wire. The copper constantan wire is made to standard T-type thermocouple specifications. This is a solid AWG 30 wire (0.25 mm conductor diameter). It is sold in 10 yard spools. T-type thermocouples can used to measure air or gas temperatures, non corrosive liquids and it can be attached to pipes or embedded into objects you want to measure. This T-type probe wire also measures down to the temperature of liquid nitrogen, - 320 F (make sure the electronic thermometer is capable of measuring that low). It is frequently used in the laboratory to measure liquid nitrogen, dry ice (solid carbon dioxide) and very cold cooling liquids in cryogenics. T-type thermocouples are also used in the wood industry for measuring wood drying kilns.