[link|http://www.science.uva.nl/faculteit/museum/remarkable.html|IBM 2321 Data Cell].

Some close-up photos at the link. On a "field trip" for IBM in late 1960's, I did get to see some units at Northwestern Life Insurance Co. in Milwaukee, Wisconsin. As I recall, the IBM CE (customer engineer, i.e. service guy) told me he had job security keeping the units going.