The Fluke Calibration 5611T is an especially versatile PTFE coated thermistor probe. With a PTFE encapsulated tip that is just 3 mm (0.12 in) in diameter and a PTFE coating that makes it resistant to most liquids, the PTFE Probe is handy for measuring in a vast variety of applications, including bio-pharmaceuticals. It's even immersible to nearly 20 feet and flexible enough that you could roll it up into a ball in your hand if you wanted to!
The 5611T's thermistor bead is encapsulated in a Mylar sleeve that is encapsulated inside a PTFE sleeve. The PTFE sleeve is then melted around the PTFE-insulated cable, forming a moisture-proof seal.