His best-known invention was the Emánuel Moór Pianoforte, which consisted of two keyboards lying one above each other and allowed, by means of a tracking device, one hand to play a spread of two octaves. The double keyboard pianoforte was promoted extensively in concerts throughout Europe and the United States by Moór's second wife, the British pianist Winifred Christie.
Maurice Ravel said that the Emánuel Moór Pianoforte produced the sounds he had really intended in some of his works, if only it had been possible to write them for two hands playing on a standard piano. Pablo Casals always believed in him and often played his works.