The Ultra-Fex was made by FEX (French EXport), later Fex-Indo (Industrie Optique). According to
McKeown's, there was a Fex camera in 1944, in 1945 a Superfex with an optical finder and in 1946 or 1947 the Ultra-Fex. They all have the same distinct Art-Deko bakelite body. There was a variety of slightly different models and it stayed in production until 1966.

It is unclear, why the French company chose the American 620 format, mainly made by Kodak, whereas 120 film from multiple companies was widely available in Europe. So only 620 film is usable (or re-spooled 120 film). The 620 spool must be an old metal type one that has a hole right through to take the feed side spindle. Modern plastic spools will not work.

Its main features are:

90mm meniscus lens,~ F11, F16, focus free, 1.5m-
Shutter B, 1/100
Size 155x87x75mm Weight  350gr.

Camera front. Lens, viewer, shutter release. Under the lens: switch for single shutter speed or B and aperture switch ~ 11 and 16, "intense" refers to the light, so the smaller aperture is on the intense side. There were versions with 2 shutter speeds and versions with a PC flash socket. Sometimes the first metal ring behind the lens is painted blue to imitate a lens coating.

Camera back. Viewer and red window.

Camera top, not extended. Film wind. Shutter locked. The film feed side is a spindle, that screws from the top right through the spool into the bottom.

Camera extended. The red arrow has to be visible.

Shutter lock open.

Camera bottom. Nothing to see, no tripod socket, would however make sense as there is a B setting.

Back deposed. You have to slide down the brackets on both sides.

Film compartment. Note the curved film plane. It avoids vignetting of the simple meniscus lens.

These are the ultimate basics of a roll film camera, focus free, single shutter speed and 2 aperture. Point and shoot only. If you choose the right film, ISO 400 in general and ISO 200 on very sunny days, you can shoot outside photos that look o.k.. The rest will be "Lomo" style. Seen the price of 620 film I would not run a roll through it. It was given to me by a friend, just for free. It's more an item for collectors of beautiful bakelite cameras.