B â™ / Convertible model. The valve system is 3 pistons. Bell has yellow brass diameter 366 mm, bore size 16.8 mm, silver plated finish. With 2 blowing pipes.
B â™ / Convertible model. The valve system is 3 pistons. Bell is yellow brass diameter 443 mm, bore size 18.5 mm, silver plated finish. With 2 blowing pipes.