D'Addario Accessories Guitar Humidifier Pro - Acoustic Guitar Soundhole Humidifier with Sponge - Non Drip - Suspends from Strings - Holds 12x Weight in WaterUNIQUE HUMIDIFICATION SYSTEM: Guitar Humidifier Pro features a two way humidity control that maintains 45 50% relative humidity, the ideal range for your instrument EASY TO USE: Simply moisten the sponge, place it in the included hygrometer, and then install it in the soundhole of your guitar. Easy to monitor and refill sponge PROTECT YOUR GUITAR: Dry air can cause wood to crack and warp. Protect your guitar from expensive repairs and preserve its