Vintage SYLVANIA model MPXIII AC operated 2-transistor FM multiplex stereo adapter. Original old Sams Photofact manual includes schematic, parts layout, voltage/resistance test charts, alignment info, repair parts list and description. 4 pages. Dated 6-1963. Manufactured by Sylvania Electric Products Inc, of Batavia, NY. This manual would make a sensational accompaniment to your retro audio equipment.