Exchange mechanism ‚Chaîne interchangeable‘ with 50 Verascope views in card-board frames

Louis Legendre was a French man­u­fac­tur­er of stere­o­scopes. He acquired the com­pa­ny of Wyten­hove in 1898.
In 1899, Legendre intro­duced a sig­nif­i­cant inno­va­tion: a chain-based stere­o­scope equipped with an inter­change­able chain and stere­oview hold­ers. This sys­tem sim­pli­fied the exchange of stere­oviews and enabled com­plete col­lec­tions to be stored and viewed using dif­fer­ent sets of holders.
Legendre’s com­pa­ny was acquired in 1902 by Mat­tey. This acqui­si­tion marked the begin­ning of Mattey’s activ­i­ties in the stere­o­scope industry.
(from: Com­pendi­um of Stereoscopes)