Stereoscope ‘Omnium’

L’Omnium is a fold­able pock­et stere­o­scope. The lens pan­el and the stere­oview hold­er are col­lapsi­ble, and the hand­grip can be unscrewed from the view­ing sec­tion. When dis­as­sem­bled, the com­po­nents can be stored in a case, typ­i­cal­ly fin­ished in bur­gundy or black.
(from: Com­pendi­um of Stereoscopes)

Fur­ther read­ing: Stere­oscopy His­to­ry Series — Lucien Bize (A. Ruiter)