The c. 1480 Memling organ upon which the modern replications are based show a 25-note instrument of two stops.
This entry describes an original installation of a new pipe organ. Identified by James R. Stettner, using information from this web site: http://music.vassar.edu/organs/. -- According to the college website, "The smallest organ in our collection is the Memling Portative, which was fashioned by Phil Levin in 1981 to resemble the instrument frequently depicted by the Flemish painter Hans Memling. It is used in performances of medieval and Renaissance music."