Yamaha YBB 621

4 front action valves, 3/4 size, Profi- class Bb- Tuba, bore 0,689- 0,728", brass lacquered, bell 14-3/8", included case and mouthpiece.

A Yamaha wind instrument is already ideal
companions on your musical journey. Now you can yours
protect the musical instrument more by extending the warranty to five years, completely free of charge if you register within 6 months of purchase. At the same time, you will get 3 months access to the premium account of the Tomplay application.
Just visit the website and follow the three simple steps described.

https://uk.yamaha.com/en/support/warranty/winds-extended-warranty.html