copied from the Loreo page
The Pixi 3D Viewer is a Parallel Format (side-by-side) 3D image viewer made of card paper. It is primarily a Computer Monitor Viewer for medium sized images. Cheap, lightweight, foldable and mailable, it folds flat to the thickness of its lenses (5 mm). It is suitable for viewing 10 – 13 inch (25 – 33 cm) wide screen images. Equivalent to 15 – 17 inch computer monitors.
 | Left: Loreo Pixi 3D Viewer made from plastic coated card paper with the inside surface printed black to create the dark viewing chamber. |
It can also be purchased from Berezin