C & W Seniors started in 1922 as model A, then came the B. there is no C, the next in 1927-28 as the D.
Then came the E with a rear shutter .
One could send the Model D back to the factory and had it up graded to an E specification.
Because the Seniors were such a good machine showmen sent them back to the factory for upgrades.
They became known as EH. They had new type film gates and were made suitable for big CinemaScope lenses of the 1950’s.
C&W Film Gates model EH