Review on TWTADE 5pcs 3M K Type 🌡️ Mini-Connector Thermocouple Temperature Probe Sensor: Measure Range -50~350°C by Tony Wylie

These are thermocouples. They work, they're pretty accurate. Nothing special. The wire is quite thin, so they react quickly. There is heat shrink tubing on each end, so I'm guessing that over time at some extreme temperatures it will come loose and the fiberglass braid (or whatever) surrounding the wire will probably start fraying? This is an assumption based on previous experience. It might not happen, and if it does, it's no big deal. They do the job, they were inexpensive.