Those are Type K thermocouples and not terribly accurate (though within a couple of degrees if the electronics are properly compensating). They are not intended to be immersed though there is a rubber insert where the cable meets the proble sufficient to keep liquid out when they are cleaned after use. The problem I've had with them is the insulation melting (though in grilling - not brewing). Note: I do not have the unit shown but rather a couple of other brands that use that same probe.
I think it was on HBT I saw where someone had added some tubing and an o-ring to waterproof the probe. I mainly like that it's cheap and I can have it as a backup to my other digi probe.
