Just be aware that their are 2 different size "Midland-Ross" Boosters. They are also fairly hard to find as a rebuilt unit, and to get parts for. Their is a 6 1/2 in, and a 7 in, or 7 in , and 7 1/2 in. I can't remember right now. The parts are the same, except for the 2 main diaphrams, one of...