Consider the following region shown in green:
It is a part of the annular cylinder with the inner radius $R$ and the outer radius $R+r$, which is cut off from the left and right. Is it possible to get this figure as a
Region in Mathematica? For the test parameters, we may consider its longitudinal length
dz = 10, the radii
R = 10,
r = 2, and the transverse length of the remaining shell
dx = 2.