Feature:1. Protection Function: The humidifier pack is mainly used to protect musical instruments from warping, cracks, and other damage caused by a lack of humidity.2. Two Way Humidity Control: This humidifier pack provides two way humidity control, and can maintain a relative humidity level of 4550% inside the instrument casing.3. Automatic Regulation: Automatically maintain the optimal humidity inside the instrument casing, no manual adjustment required based on season, location, or temperature.4. Applicable Instruments: These humidifier packs are suitable for acoustic guitar, classical guitar, electric guitar, bass, violin, cello, banjo, mandolin, ukulele, and more.5. Convenient Use: These humidifier packs are compact and lightweight, can be placed inside the instrument casing or at the sound hole, convenient and practical.Specification:Item Type: Guitar Humidifier PacksApplication: Acoustic Guitar, Classical Guitar, Electric Guitar, Bass, Violin, Cello, Banjo, Mandolin, Ukulele, and morePack Size: Approx. 12 x 7.5cm / 4.7 x 3in.Package List:3 x Guitar Humidifier Packs