D'Addario Planet Waves PW-HPRP-03

Features
3 replacement packs for the D'Addario Two-Way Humidification System
Automatic humidity control protects your instrument against warping, cracks and other damage cause by lack of humidification
No more manual adjustments based on seasonal changes, geographic locations, temperature, or other factors Unlike refillable humidifiers
Eliminates the guesswork and anxiety of maintaining your instrument’s proper humidity level
No water, no drips, no mess
Custom made by Boveda fo D'Addario