Technical description: Blackwood with german silver ferrules and keywork. Five pieces: mouthpiece, barrel, upper section, lower section, bell. Mark on back of instrument is widely believed to indicate a Martel clarinet. Average Boehm system but with long tailed throat A♭ key to enable an `British' fingering with R2. All L4 levers on a single pivot. Flat spring on F♯₃/C♯₅. 17 keys, 6 rings.
L0: T + ring F₄/C♮₆; speaker.
L1: T + ring F♯₄; throat A♮.
L2: T + E♭₄/B♭₅ corresponding ring; throat A♭.
L3: T; 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.
R2: T + ring B♮₃/F♯₅ via correspondence.
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.
Used as a pair with (5189).