Features: 1.The acoustic guitar sound hole cover humidifier is the humidity guardian of acoustic guitar, which can effectively prevent guitar deformation and prevent cracking and other symptoms. 2.With sound hole humidification function, the tool can maintain humidity at 45%?65%. 3.This guitar sound hole cover humidifier is composed of a soft rubber cover, a cover surface, a water retention sponge, a moisture?proof net and a bottom cover, which can protect your guitar well. 4.The hole cover is used as a normal sound hole cover to eliminate unwanted feedback, such as howling. 5.The soft rubber of the product covers the insert edge and will not damage the guitar. 6.The product is easy to use and operate. Just moisten the supplied sponge and install it to reuse the humidifier. specification:Item Type: Acoustic Guitar Sound Hole Cover Humidifier Material: ABSandspongeandrubber PackageList:1 x AcousticGuitarSoundHoleCoverHumidifier2 x Guitar Picks (Random Color)