Product review (1 stars): Dew Point Displayed - UPDATED
UPDATE: bought three of these four months ago. As of right now, one works, one has the display malfunctioning (illegible) and the humidity accuracy of the other has drifted more than 10% from the only one that is working correctly. That's a 67% failure rate. If you buy it, good luck rolling the dice: you should get a good one, one out of three times.

Original review:
Finally, a constant display of dew point. America seems fixated on the useless relative humidity number and the vast majority of weather stations only provide relative humidity. If I say the relative humidity is 50% and ask if that means it's uncomfortable, the only thing you can say is "Maybe", but if I say the dew point is 65 degrees, you can say "Yes!" Read about it on the web and you will see for yourself the value of dew point.

This is large enough to be easily read and hangs on a wall nicely. It also has a stand that also holds it nicely. The probe can be extended from the base by a little over a foot so, it would be difficult to put the probe outside conveniently and the wire is a little thick to string it along a door or window crack. However, these are cheap enough that you can buy a couple and place one in your window or just move it outside briefly. The dew point (and the RH - if you actually believe that number is meaningful) update within a few seconds.

Why 4 stars instead of 5: I bought three of these and found one of them to show all three data points significantly below the other two. This indicates variability in manufacturing. There is no way to calibrate these. So, when you receive it, test the temperature by comparing it to another thermometer that you know to be accurate and test the relative humidity using the saturated salt solution test procedure. This can be found on the web and is very easy to do. Essentially, it creates a fixed 75% RH level in a closed container (a good way to test any hygrometer). If the All-Sun displays 75%, after 12-24 hours, it's good.