Product review (1 stars): A much needed innovation, with one small criticism.
D'Addario/Planet Waves has done it again! They're changing the game of guitar add-ons and accessories, and I sincerely thank them for it.

The humiditrak was a much needed innovation in the guitar hygrometer world, it solves the common issue of traditional hygrometers: not being able to tell what the humidity levels are throughout the day without opening your case every hour. Fluctuation in guitar humidity and temperature is so important with high end acoustics, and we finally have a product to combat it.

The iPhone app is extremely simplistic and quick to use, it updates very quickly once opened.. and I have no complaints about it. The interface is nice as well.

As far as the hygrometer itself, it's actually extremely accurate as advertised. I tested it through the salt test (Youtube it), and tested it against my Caliber IV, and it was right on the dot. I'm super impressed, as this was my biggest concern when buying.

Now here's my criticism. The reason I gave it a 4/5 instead of a 5/5 is because it has one flaw, and it's the fact that your phone obviously cannot reach the Humiditrak at home while you're away. A quick solution to this, in my opinion, would be for D'Addario to also create a Desktop app for your computer. My computer is always home and within reach of the Humiditrak, so I could come home and see how the guitar was doing all day with my A/C off. I believe it would also then be able to sync with your phone at that point.. so I think this addition would be perfect. Let me know if you disagree!

D'Addario, please let me know if a Desktop app is doable, or if it's already in progress! Please include Mac if so!! Thanks a bunch.

edit: Been about a year, no longer accurate. Disappointed.. especially knowing I spent so much money on this. Don't buy till improved.