Stereoscope ‘Mignon-Stéréo’ with Original Storage Box and Image Set

The name sug­gests that it is a French stere­o­scope, but the Mignon-Stéréo is of Ger­man man­u­fac­ture. The device is intend­ed for small 3 x 6.5 cm glass stere­oviews that were made specif­i­cal­ly for this view­er. The Mignon-Stéréo was mar­ket­ed as The small­est stereo­scop­i­cal appa­ra­tus of the world.

(from: Com­pendi­um of Stereoscopes)