John is right--11x14 backs for Century studio cameras are incredibly rare. Over time, portraits were taken on progressively smaller formats. The 11x14 cameras were much less common to begin with, and the larger backs were often misplaced or discarded as studios reduced format sizes. Some 11x14 Empire State cameras have backs that may fit Century Studio cameras. The ridiculously rare 11x14 Kodak 2D back will also fit. My recommendation is to buy any 11x14 back you can find and make an adapter to fit your studio camera. All 11x14 backs are rare, so a little patience helps. Good luck!