D'Addario Humidipak Two Way Humidification System Replacement Packets, 3-pack; PW-HPRP-03 D'Addario brings you Boveda's patented technology; part; our instrument care line. Humidipak; the only maintenance free, two-way humidity control system for guitar; automatically maintains the optimal 45-50% relative humidity level within your instrument case, eliminating the guesswork and potential mess related; refilling; humidifier. Unlike refillable humidifiers, this system provides true two-way purified humidity control; adding and removing moisture; demand; more manual adjustments based; seasonal changes, geographic locations, temperature; other factors. Humidipak comes with; packets and; soft mesh pouch that will not harm your instrument's finish. These packets last between; and; months and should always; kept; sealed environment like; hard-shell case. Once the packets become firm, discard and replace using the; refills that come; the Humidipak Replacement Pack (PW-HPRP-03). This all new, reformulated, patented two-way humidification system maintains 45-50% relative humidity which eliminates all maintenance and guesswork. This system; recommended; taylor guitars and others for maintaining the stability and playability; your instrument. Note: Humidipak; designed for restoring and maintaining instrument humidity. This product; not intended for de-humidification; high humidity environments; The first two-way humidification system that maintains; constant 45%-50% relative humidity level within your instruments case Protects your instrument against warping, cracks and other damage cause; lack; humidification; more manual adjustments based; seasonal changes, geographic locations, temperature; other factors Unlike refillable humidifiers Eliminates the guesswork and anxiety; maintaining your instrument's proper humidity level; water; drips; mess Custom Made in Boveda for D'Addario;