Planet Waves PW-SIH-01 Humdifier, humdifying system, ideal for acoustic guitars, ukulele, mandoline, bowed instruments and woodwind insturments, emit slowly and steadily moisture to the instrument, easy filling with water
I use these in the headstock compartment of my acoustic guitar cases with the planetwaves PW-GH-HTS humidity control & sensor system with the sound hole humidifier taking care of the other end and they serve that purpose very well even though it's not exactly what they were designed for. When I bought my first really good acoustic I used the Planetwaves Humidipack system which is fantastic & has the added bonus of absorbing excess moisture when the humidity level gets to high. I never had a problem with that system & found it excellent, & I have never heard of anyone ever having any problem, but the idea of a pouch of liquid/gel hanging in the sound hole of my pride & joy became to much for my nerves so I switched. I'd like to repeat I have never heard of any problem with the humidipaks leaking, but I just wanted 101% peace of mind. With the PW-SIH-01 all moisture is held by a sponge so there is definitely absolutely no chance of leaks or spillages. Great little product.
Good to keep in the guitar case to keep the instrument in a perfect environment and remain the quality of the guitar with a little moisture. Small and simple to operate. Works great both with classical guitar as with my guitalele.