The Isonorm fonts comply with the general requirements for lettering to be used in technical product documentation as defined in 1980 by the International Standard Organisation in ISO 3098. There are various digital versions, by URW++, Mecanorma/International TypeFounders, Inc. (drawn by Lennart Hansson), Scangraphic, and Elsner+Flake. The latter two come in a second styles that is distinguished by an alternate ‘a’. FontFont’s FF Isonorm adds a monospaced style.