PerfectPrime TL0024TT, Thermocouple T-Type Low Temperature Sensor/Probe, -200~260°C / -328~500°F, 2 Meter Long

I am finishing my PhD in chemistry and we do a lot of selective trap to trap distillations where we pull a vacuum of about 0.1 Torr and separate components of a synthesis based on their volatility. I regularly have to make acetone/liquid nitrogen baths between -20 to -70 degrees C and an error in the temperature readings of the baths can be disastrous.These thermocouples are great. I own 6 of them which is more than I need but I love gear. They are very responsive and as the description says the error in the reading is about +/- 1C. I calibrated them to agree with boiling water temperature that day based on the pressure, and afterwards just wanted to see what they read for liquid nitrogen. It registered at -192C which only 4 C off at such a low temperature is not too shabby.If you require even more precision get at least a lower-mid range Pt100 RTD sensor and a decent temperature gauge.

Works well for monitoring cold bath temperature

Very accurate probe at -75 degrees C. Probe/junction is not water proof. User needs to make provisions to seal the junction.

The thermocouples performed to their stated specifications, product quality was good, packaging and labeling was also excellent. I did not get any calibration data, we have our own metrology lab that would perform. Considering that excellence is the norm, the items were normally good.

Installed the probe and it works well to monitor the temperature of a -80C freezer.So far so good...