B ♭ / Convertible model. The valve system is 3 pistons. Bell is yellow brass diameter 280 mm, bore size 14.5 mm, silver plated finish. Two blowing pipes
B ♭ pipe convertible model. Valve system is 4 pistons. The bell has a yellow brass diameter of 280 mm, the bore size is 1st to 3rd = 14.5 mm, and the 4th = 15.5 mm. With 2 blowing pipes.
