DIN 108-9
DIN 108-9 Slide projectors and slides; straight cartridge 5 × 5-36 and 5 × 5-50; gauge for cartridge profile and gear system
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 09/01/1988
standard by Deutsches Institut Fur Normung E.V. (German National Standard), 09/01/1988