A wood­en tray con­tain­ing 20 glass slides can be insert­ed by flip­ping down the front of the view­er, then, by mov­ing a knob, locat­ed on the right side, up and down, one slide after anoth­er can be exam­ined. The slides are pulled up by mag­nets which con­nect to met­al strips attached to the glass slides. Below the knob, a brass arrow will point to the num­ber of the slide that’s in view and allows nav­i­ga­tion to a spe­cif­ic slide. For that, the knob has to be stopped at an inter­me­di­ate posi­tion, which unlocks the tray move­ment. This posi­tion is also required to exchange the tray.
The view­er has a detach­able base con­tain­ing two draw­ers with three trays each, mak­ing it pos­si­ble to store a total of 120 slides. A tilt­ing mir­ror for bet­ter light­ing is attached to the back of the viewer.
The stor­age desk con­tains sev­en draw­ers on each side hold­ing six trays each, result­ing in a capac­i­ty of 1680 slides in total. This stor­age desk doesn’t appear in Plocq’s cat­a­logues, but was most like­ly built to order by a pro­fes­sion­al car­pen­ter mak­ing this ensem­ble unique.