Product review (1 stars): 1 of 2 worked.
Bought 2 of these units.  One read exactly 75 on the salt test.  The other read 68, well outside of the tolerance.  The second one is going back.  The low rating is for the hassle of having to fish through these units in order to find a good one. I will revisit this review after I've had the "good"  one for a while.  I want to have a better idea of how it holds up.