The Mass of the mouthpiece refers to its overall weight. The weight is determined by the outside shape and type of materials used in the construction. The trumpet wall to include the material, weight, thickness, heat-treating, stress relieving, or annealing will not affect the resonance characteristics of the trumpet. These properties will have an impact on the amplification of the partials created by the trumpet air column .
Some players feel the added mass helps balance the horn.
The choice is yours. GR Technologies offers a variety of different mass mouthpieces.