The camera's capacity is 100 ft. A 400-ft magazine (on the Rex 5 – or converted Rex 3 or 4) can be attached to the top of the camera. From the beginning, it offered automatic film threading, a clutch for disengaging the drive spring in order to crank the film by hand forward and backwards unlimited, and a cut-off turret disc that is not wider than the camera body in center position. Stepless speed control was available between 8 and 64 frames per second. Early cameras have a 190 degrees opening angle shutter. A few years after their introduction the H cameras could be equipped with an accurate single-frame counter. That accessory was incorporated into all H camera models since 1946.