Foldable Stereoscope

Eugène Hanau was a man­u­fac­tur­er of cam­eras and a pub­lish­er of stere­oviews. In 1879, he acquired the pub­lish­ing busi­ness of Jules Marinier. Hanau pro­duced both con­ven­tion­al cam­eras and stereo cam­eras. From 1901, the busi­ness con­tin­ued under the name E. Hanau et fils.
Hanau used the ini­tials E. H. when pub­lish­ing stere­oviews. The reversed ini­tials, H. E., are also thought to refer to Hanau and have been iden­ti­fied on stere­o­scopes sold by the company.
(from: Com­pendi­um of Stereoscopes)