The Mamiya Universal Press Camera was popularly used in the late 1960s by journalists and press photographers. It had a unique feature - swappable film backs. This would allow a photographer to have multiple rolls of film loaded on a shoot. They could shoot indoors with a high speed film, and if the event transitioned outside, they could swap the film back out mid-roll for a lower speed film. The model I have came with a 6x9cm film back, which is an absolutely massive negative! Other film backs were available, such as 6x6 and 6x4.5.