Features: Humidification System: Guitar Humidity Packet is maintenance-free, two-way humidity control system for guitar. Includes pouches and guitar humidifier packs. Protect Your Guitar: Protects your instrument against warping, cracks and other damage cause by lack of humidification. Two Way Humidity Control: The first two-way humidity control that maintains a constant 45%-50% relative humidity level within your instruments case. Automatic Adjustments: No more manual adjustments based on seasonal changes, geographic locations, temperature, or other factors unlike refillable humidifiers. Automatic Humidifier: It automatically maintains the optimal 45%-50% relative humidity level within your instrument case, eliminating the guesswork and potential mess related to refilling a humidifier. Specifications: Material: Non Woven Fabric, Natural Plant Fiber Materials Color: As The Picture Shows Style Options: 1 Set/3 Bag Supplements Size: approx.12x9.5cm/4.72x3.74in (More Size Detail, Please See Photo.) Package Includes: 1 Set of Guitar Humidifier Maintain Kits note: Please allow 1-2cm error due to manual measurement. Please make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thanks!