Mazzeo system

• The throat B using the A key and any one or combination of left-hand second or third finger or right-hand first, second, or third fingers to operate a linkage opening the third right-index-finger trill key, rather than using the inadequately vented register key to obtain that pitch; the same fingerings, minus A key, produce A; traditional B and A fingerings are also available;
• A left-hand-thumb plateau key;
• A ringless bell with less flare.

• An E/B key playable with the thumb, first, and third fingers and D/A key on the left-hand side;
• An articulated B to C keys;
• An alternate left-hand A/E key.