The Ernie Ball Soundhole Cover suppresses unwanted noise and feedback, maximizing the output of your acoustic-electric guitars. The soundhole cover fits acoustic soundholes with a diameter of 8,6cm (3-3/8"), while the durable rubber material is soft and will not damage your guitar’s surface. Protect your guitar from that undesired screech and hum while eliminating dirt and debris inside your guitar with the easy-to-install, no tools required acoustic soundhole cover from Ernie Ball.