I just found the remains of mine, I guess it was Pyrex. Not expensive, and it would still be working, but it had a little magnet on the back to keep it on the fridge. My boys decided to use it as the top of the tower for thier magnet set, and it goofed up the electronics for the readout and my temp was all over the place.
So, moral of the story, don't play with the magnet set near it!
Not that there's anything wrong with that.....