Mandolin Overtone Suppresors NOTE....I will include 2 spares so you get 6 UK delivery only. Harmonic suppression on a mandolin is a method to reduce unwanted harmonics that can be produced by the strings between the bridge and tailpiece. This can improve the tone of the mandolin and is especially important for professional musicians and anyone who wants the best tone from their instrument. One way to achieve harmonic suppression is to use rubber grommets, also known as harmonic suppression grommets or mandolin grommets: How to use Slip the grommets between the string pairs between the bridge and tailpiece. Benefits Can eliminate tailpiece buzzing, overtones, and make chops fuller and more percussive.