Product review (5 stars): Simply Amazing Meter
This meter is the one.  I have reviewed many meters before deciding on this one.  Another review says the meter is too slow to respond and that a $3.00 thermometer is as good.  Apparently the person does not know that a hygrometer is slower to respond.  It's is so much quicker than a sling psychrometer and also no need to take out the Psych Chart to calc dew point.  The unit provides a wealth of information quickly and 99 storage registers for readings.  Great for balancing, system cooling performance evaluation, diagnostic tool, verification of tstat humidity reading, etc...  Have I gloated enough, buy it you won't be sorry you spent the money on this unit.