Features 1、Double Functionality: This acoustic guitar humidifier serves as both a humidifier and a dehumidifier. Simply moisten the included sponge to use it as a humidifier or utilize the desiccant(not included) to absorb excess water, helping maintain an optimal humidity level around your guitar. 2、Excellent Rubber Material: The insertion edges of the acoustic guitar humidifier cover is coated with soft rubber to guard the guitar's finish, ensuring that it won't scratch or damage the instrument, even with frequent use. 3、Accurate Humidity Monitoring: Equipped with a physical dial, this guitar humidifier cover accurately displays humidity levels inside the guitar body in real time. It's easy to read and stylish, helping to maintain the optimal humidity range of 45%-60%, important for the guitar's well being and performance. 4、Reduces Unwanted Feedback: This music instrument humidifier cover doubles as a regular sound hole cover, effectively minimizing unwanted feedback during performances, thus enhancing sound clarity and performance quality. 5、Universal Compatibility: Specifically designed to fit sound holes with a diameter of 100-103 mm, this guitar soundhole humidifier is suitable for all wooden guitars, including folk and classical models, making it a versatile addition to any guitarist's toolkit. Specifications: Item Type: Guitar Soundhole Humidifier Model: FH-10 Material: ABS, Rubber Package List 1 x Guitar Soundhole Humidifier