Yamaha YSL-640 Tenor TromboneYamaha Professional model trombones have long been popular thanks to their quick and agile response, highly accurate intonation, and rich warm tone. The new Pro series have kept all these fine qualities, while adding some design features from our top of the line Xeno trombones. Their broad sound has a well defined tonal core for excellent projection in all registers at any dynamics. The series offers two different bore sizes to meet individual playing