These typically do not have an air chamber and are named only because of their external shape.
A person floating in the air chamber would feel mighty helpless.
Then came an air chamber and behind it 2 double doors again.
A minute's climb brought them into a great domed air chamber.
An uncanny shape came into the light of the air chamber.
The large tears in the air chamber made it worthless.
He got up and opened the little air chamber.
For some reason I don't know, this house is equipped with a special air chamber.
Initially the water level will be near the roof of the air chamber.
In practice, however, it is common for each individual reed to have its own air chamber.