1976 Mamiya C330f  has the optional Porro finder installed as well as an auxiliary handle with shutter release trigger.  This model has the removable back. The pressure plate rotates for either 120 or 220 film. The rotation of the pressure plate also resets the film counter and film advance mechanism.  This is a very popular user camera and my father, who bought it in 1976 at 47th. Street Photo, only parted with this camera when he went completely digital. I still use this camera on a regular basis. Interchangeable lenses in this kit  include an f2.8 / 80mm Sekor and a f4.5 / 180mm. Lenses are available from 55mm to 250mm for this camera. A 'paramender' is seen in the last photograph, this item attaches between the camera and tripod and moves the camera up (or down) to correct for parallax when doing close-ups.