Ultra FBR2 Feedback Buster for Acoustic Guitars<div style="text-align: left;"><strong>[Product Information]</strong><ul><li><span class="a-list-item"> Plugs Right into the Soundhole </span></li><li><span class="a-list-item"> Fits Soundholes 3 7/8"-4" </span></li><li><span class="a-list-item"> Model# FBR2 </span></li></ul></div><img src="http://ecx.images-amazon.com/images/I/41mmQTU8j8L.jpg" noproxy>