Planet Waves Humidipak: Two-Way Automatic Humidity Control Made Simple. The Planet Waves Humidipak is the only maintenance free, two-way humidity control system for guitar. It automatically maintains the optimal 45-50% relative humidity level within your instrument case, eliminating the guesswork and potential mess related to refilling a humidifier. Unlike refillable humidifiers, the Humidipak system provides true "two-way" purified humidity control by adding and removing moisture on demand. No more manual adjustments based on seasonal changes, geographic locations, temperature, or other factors. The Humidipak Kit comes with 3 Humidipaks and a soft mesh pouch that will not harm your instrument"s finish. Does my guitar need to be humidified? Yes! In fact, it’s essential to humidify all wooden instruments. Lack of humidity is the number one cause of all instrument repairs. Here are some common symptoms of a dry instrument: Sharp fret ends Neck bow (slight curve in guitar neck bringing the fretboard away from the strings) Sunken top Lifted bridge Lower string height, buzzing notes Cracking of the neck and/or guitar body Changes in the instruments tone How do I use the Humidipak System? Simply place two packets in the included soundhole pouch and one packet in the included headstock pouch. Hang the soundhole pouch inside the guitar by draping it over the two middle (G and D) strings. Lay the headstock pouch in the top compartment of the case under your guitar"s headstock. Close the case and THAT"S IT! When playing your instrument, leave the pouches inside the instrument case and secure the lid. This will maintain the proper humidity level inside the case and allow you the maximum life of the Humidipak packets. As long as you can press the packets with your fingers and feel movement of the contents, the packets are working. Once the packets become solid, discard and replace with Humidipak replacement packets. (PW-HPRP-03) How long will the packets last? On average the packets will last 2-4 months depending on the geographic location and the conditions of which the instrument is exposed to. This is calculated on using the Humidipacks year round. You may experience months where the packets last longer and months where the packets dispense faster. The Humidipak System is a humidity "maintenance" device. If your guitar has not been previously humidified and/or is showing signs of lack of humidity, the packets will dispense at an increased rate due to the fact that the instrument is in a dry condition and will soak up the moisture it desperately needs to reach equilibrium. In these instances, pre-conditioning your instrument with the Planet Waves GH soundhole humidifier is recommended. For more information, see the Humidipak FAQ page on the Planet Waves website.