Clarinet. Nominal pitch: B♭.

Technical description: Blackwood with silver plated german silver ferrules and keywork. Five pieces: mouthpiece, barrel, upper section, lower section, bell. The main feature of the Mazzeo system is that it has one proper tone-hole for the register key and another for a good in-tune throat B♭, instead of using one key compromising between these different requests. B♭ key operated by L2, R1, R2, on R3 articulated. Closed with L1 and L0. Plateau key for L0. Ringless bell aids in weight reduction. 19 keys, 6 rings. L0: plate F₄/C♮₆; speaker. L1: T + ring F♯₄; throat A♮; throat A♭. L2: T + E♭₄/B♭₅ corresponding ring. L3: T + ring; cross E♭₄/B♭₅. L4: C♯₄/G♯₅; F₃/C♮₅; E₃/B♮₄; F♯₃/C♯₅. R1: T + ring B♭₃/F♮₅ via correspondence; side E♭₄/B♭₅; side F♯₄/C♯₆; trills 1-2; throat B♭. R2: T + ring B♮₃/F♯₅ via correspondence; throat B♭. R3: T + ring B♮₃/F♯₅ via correspondence; cross B♮₃/F♯₅. R4: G♯₃/E♭₅; E₃/B♮₄; F₃/C♮₅; F♯₃/C♯₅. Keymount type: screwed in pillars. Keyhead type: modern.