The Unidisc is designed to produce 3 mm diameter discs for electropolishing, and subsequent TEM examination, from sample strips.

The punch and die are replaceable items made from hardened tool steel. The standard model produces 3 mm discs for TEM from sheet/foil samples with minimum distortion. Optional models produce discs from 1 to 6 mm in diameter. Examples of the use of these includes the production of 1 mm discs of highly radioactive materials which are pressed into holes punched in non-radioactive 3 mm discs and the composite disc thinned. This reduces the radiation dose to the personnel involved. The larger disc specimens are used in SEM.

Sample strips are fed into the side of the Unidisc. When the handle is pulled, the strip is trapped between two rigid metal die faces. The punch then pierces the tightly held sheet and ejects the disc into the collection tray. Deformation is confined to a much localized shear zone at the edges of the disc away from the central region which is later thinned using either the twin jet electropolisher or the single jet electropolisher.