SKB Guitar Humidifier 
Care and feeding of your beloved acoustic guitar...
Temperature and humidity are two of the primary forces acting upon your beloved acoustic guitar. Some good tips to keep your instrument playing nice for many years can be found at
http://www.acousticfingerstyle.com/CareAndFeeding.htm and
http://www.larrivee.com/flash/features/education/humidity/humidity.html
The SKB Clip 6 Humidifier
I recently upgraded my acoustic humidifier system to the SKB Guitar Humidifier. My last humidifiers had to be pushed in between the strings and water injected via a plastic syringe through a small hole in the top of the humidifier.
The SKB Clip 6 humidifier is really nice as you can fill it from vented holes and you don't need to insert it between strings. It simply clips over the strings with a very easy to insert and remove mechanism.
It also comes with a solution that includes
propylene glycol, a common liquid used in cigar humidifiers among other things. After using up the initial solution, you simply continue to add distilled water every so often.
Check it out at
http://www.musiciansfriend.com/product/SKB-Guitar-Humidifier?sku=421906
