Feedback Buster FBR2 Acoustic Guitar Soundhole Cover

The Feedback Buster FBR2 is a soundhole cover that fits into the soundhole of an acoustic or acoustic-electric guitar to reduce low-frequency feedback at higher volumes. Its tapered rubber design fits sound holes of roughly 3 7/8 to 4 inches (about 100 mm) and installs under the strings without harming the guitar's finish. It can also lower the guitar's acoustic volume for quiet practice.