Guitar Sound Hole Cover Moisturizer with Built-in Sponge Guitar Soundhole Humidifier with 2pcs Mouldproof Natural Wood Pulp Sponges Features: Guitar sound control humidifier, rubber can completely close the sound control, it is not volatile after humidification, and it will not damage the paint surface when fixed. The use of natural wood pulp sponge has strong water absorption, and it only takes 3 seconds from dry to full water absorption. Ensure the humidity in the guitar resonance box, prevent the box from cracking, and increase the service life of the guitar. Two piece mouldproof sponge for replacement and long-term use. Suitable for folk classical guitar. Specifications: Material: ABS+rubber Item Size: 110 * 110 * 12mm / 4.33 * 4.33 * 0.47in Item Weight: 55g / 1.94oz Package Weight: 60g / 6.12oz Package Size: 16 * 14 * 2cm / 6.30 * 5.51 * 0.79in Package List: 1 * Humidifier 2 * Sponge