Kodak Ektalite 1000 Instruction Manual page 11

Operation
Replace the cover (or lock ring) by turning it clockwise until it is secure.
A098_0052AC
Rear-Screen Projection
You can easily adapt a show from front- to rear-screen projection.
Remove each slide from the tray and turn it horizontally (keeping the
slide upside down). This will give the projected slide a mirror image on
the screen. Insert your first slide back into the first slot in the tray.
Replace the transparent cover (or lock ring).
2
Front Rear
Projection Projection
KODAK EKTALITE Slide Projectors 53