I tend to agree with you Bill. I've done some testing with the diaphragms and when I stick them in the freeezer at 0° they are slow to respond and in the fridge at 36° they don't respond at all. Tested a few of them and they all seem to be calibrated the same. I truely think it was just a sales gimmic.
There was a guy back east or up north, don't remember which, that sold them with out a core. It was mentioned in a thread here a couple of months ago if you want to do some searching.
DG
