The Upper joint: The Low E bass clarinet manufacturer tells you that the upper joint of the clarinet is left-handed and requires a high degree of skill in clarinet manufacturing. The sound hole is pressed by the ring finger of the left hand, some have a sound hole key machine, and some do not. It's more and more common to have no key presses these days, because it's the best thing to do.

The Lower joint: The Low E bass clarinet manufacturer tells you that the lower joint of the clarinet is the right-handed part, and is manufactured with the right rhythm as the top priority.
The Speaker tube: The Low E bass clarinet manufacturer tells you that the speaker tube of the clarinet, also known as the bell, is the part that expands the air column in the tube to the outside of the tube body. This makes the bass range pure and thick, while also ensuring intonation.
The above is the Low E bass clarinet manufacturer's introduction and analysis of some of the components of the clarinet, hope it helps you.