Guitar Humidifier System - Humidity Packet Maintain Kit - Automatic Humidity Control System - Maintenance-Free, Two-Way Humidity Control System for Guitars Applicable scope: Acoustic Guitar, Classic Guitar, Electric Guitar, Bass, Violin, Cello, Banjo, Mandolin, Ukulele, etc. HUMIDIFICATION SYSTEM: Guitar Humidity Packet is a maintenance-free, two-way humidity control system for guitars. PROTECT YOUR GUITAR: Protects your instrument against warping, cracks, and other damage caused 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 instrument's case. 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. AUTOMATIC ADJUSTMENTS: No more manual adjustments based on seasonal changes, geographic locations, temperature, or other factors, unlike refillable humidifiers. Color: Black Material: Composite material Package Contents: 1 set guitar automatic humidistat (includes 3 refill bags) Only the above package content is included; other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture to be slightly different from the real thing. Measurement allowed error is +/- 1-3 cm.