Boost It! For the serious musician and enthusiast. Material: Wood and best quality Veg Tanned 3mm leather with engraved design. This piece is made to measure. Acoustic guitars have a big sound, due to their large hollow body, where all the sound reverberates within the body. This same design also lets in external sounds that bounce around in the body, and if one of these is the sound of the guitar playing back through a speaker then you get what is called feedback. The Merko Boost It! is terrific filling the sound hole of your acoustic guitar to eliminate feedback when using the internal pickup during performance. It is a must have for any performing guitarist who uses foldback, or in a live situation where the amount of stage noise guarantees instnt feedback in your acoustic guitar. Suitable for acoustic steel and classical. If you would like to order you will need to supply us the the size of your sound hole. Please measure across from edge to edge at the centre of the sound hole. We will make Boost It! a fraction smaller than your measurements. As Boost It! is well balanced it will not fall out and being a fraction smaller it won’t damage your instrument.