This was the middle model of Zeiss Ikon's folding cameras: the Ikonta, Contina and Contessa Many were equipped with a Novar lens in a Prontor shutter. The more desirable models have a coated f/2.8 45mm Tessar lens in a Synchro-Compur shutter.
The Contina II has an uncoupled rangefinder. You focus through the circular window on the back of the camera while rotating the knob on the top deck with your right-hand thumb and index finger. When the image is in focus, read the setting from the scale and set the lens to that distance. Set the aperture and shutter speed, and you're ready to take your photo.
Use the rectangular window to compose your shot and release the shutter. Like the three cameras -- Ikonta, Contina and Contessa -- in this series, it uses a front-mounted shutter release.
The camera folds to protect the lens. The film-advance and rewind knobs are located on the bottom of the camera. The top-deck knobs are for focusing and a film-type reminder.
It's a wonderful little camera with a first-class lens. I wouldn't use it for sports photography, but as an everyday shooter, it's fine.
Zeiss Ikon later replaced the folding cameras with rigid-front cameras that lacked the panache of the folding cameras.