Valve trombone.

Technical description: Nickel-plated brass; French bell rim. Long main tuning-slide (maximum extension 217mm) with restraining screw ligature on ascending outer. Three incised rings on descending inner slide marking slide extensions of 35mm, 134mm, 184mm. The 3rd valve lowers by 4 semitones. With fitting for music-card holder.; Nominal pitch: D?.; Type or system: Système Belge.; ; ; ; Usable pitch: Probably built for use at circa A?=|446|Hz.;