Jo Ral TRB-6L Large Tenor Trombone Adjustable Cup Mute This all-aluminum cup mute produces a smoother, richer sound for tenor trombones Lined with a neoprene rubber rim that eliminates vibrations It is easily installed by simply moving the cup up to the desired length for a tight fit The corks may be reshaped for optimal acoustical placement The Large Bell Model is for trombones with a bell larger than 8.5