Technical description: Silver-plated brass. With alternative leadpipes, lengths 162 (trumpet) and 157 (cornet), which slide into the mouthpipe and are held in position by a ligature screw. The alternative leadpipes give the instrument either a trumpet bore profile or a cornet bore profile and require the use of either a trumpet mouthpiece or a cornet mouthpiece respectively; however the difference is not great and the bore profile with the trumpet leadpipe is close to a cornet bore profile. The main tuning-slide has a patented doubly-adjustable stop so that it can function as a B♭-A quick-change shunt with both positions pre-set. With alternative valve tuning-slides and auxiliary main tuning-slide (piano slide) for low pitch. Valve type: 3 Périnet valves, top-sprung, alignment by three-armed washer under the spring engaging with slots in the inside of the valve casing.
Signature: Stamped on bell "UNION" / shield containing "MPBP / B&SW" / "LABEL" and engraved below "COLUMBIA / PATENTED / Harry B. Jay Co. / CHICAGO"; stamped on valve casings "1", "2", "3"; on 2nd valve casing "2978"; on shunt adjustable stop "PAT 9-12-11".