A booster converts a Classic mouthpiece to a HeavyTop by adding extra mass which fits snugly around the existing mouthpiece. The boosters extra weight helps to transfer more energy through the horn and to the bell, resulting in a more powerful sound, more secure high register playing and more focused tone. Extra mass gives greater projection and also darkens the sound. The tone develops a deeper core and takes on a darker quality, giving a greater depth even at extreme volumes and ranges without the sound breaking up. This extra projection is very useful when playing in a very large venue or in a situation where maximum volume is required. Some of the sparkle in the sound will be lost, so it useful to be able to add the booster for, say, a concert in a stadium and remove it for a chamber music performance or an intimate jazz gig. The booster will add variety to a players sound and give options for different playing situations. Some players who put a lot of energy through the instrument will find the booster useful to stop the sound becoming too bright and overbearing, adding, instead, greater focus and projection.