The stere­o­scope car­ries the name Leroy, although the name­sake played no role in its devel­op­ment. The man­u­fac­tur­er of the stere­o­scope, Émile Guérin, con­tin­ued the com­pa­ny of Lucien Leroy and retained the estab­lished name Leroy as a brand.
The Stéréo-Classeur Leroy is a com­pact stere­o­scope with a dis­tinc­tive mech­a­nism. The glass slides are lift­ed by being clamped between two grips posi­tioned at the sides of the device. In most tray-based stere­o­scopes this move­ment is pro­duced by two met­al fin­gers that rise from the bot­tom of the hous­ing. Such a mech­a­nism requires addi­tion­al space beneath the body of the view­er. The Stéréo-Classeur Leroy avoids this require­ment through its side-mount­ed arms, which con­tributes to the com­pact dimen­sions of the stereoscope.
(from: Com­pendi­um of Stereoscopes)

Fur­ther read­ing: Stere­oscopy His­to­ry Series — Bazin, Leroy & Guérin (A. Ruiter)