A folding stereoscope small enough to fit easily in a pocket. The ground glass support allows for both glass and paper stereoviews. This example is designed for 6 × 13 cm views; a 45 × 107 mm version was also available. Focusing uses a rack and pinion mechanism to vary the distance between the lenses and the view.

A series of acquisitions in the early 1900s grew the Mattey company into one of the leading manufacturers of stereoscopes in France. The business suffered during WW I, but the 1920s were productive with a number of new stereoscopes introduced, including the Educa viewer. The company continued through much of the 20th century, finally ceasing business in 1993 (Ruiter 2025).