The use of pneumatic and electric actions were introduced during this period, as the specifications and voicing became determined by the tonal and musical ideals of the romantic period. Innovations by Gustav Rieger included combined registers — using "extension" to get two stops out of one rank — and free stop-combination based on a mechanical action (used on the 1890 concert organ at the Deutsches Haus, Brno). There were 1072 organs on the firm's opus-list by the end of 1903, which saw the death of Otto and the end of an era.