In many respects, the simplified model's mechanism was also the simplest to operate. A crank handle, located on the right side, turned the smaller of the two wheels (see illus below). The wheel, or disk, had detents at the top and bottom, and raised or lowered the slides with a small lever and bell crank. When the slide was in the bottom detent position, the mechanism could be declutched and the frame changed by merely pushing in on the frame counter knob. Fancier models required the operating lever be pushed all the way down and help, or the front door opened to change frames. The mechanism operates smoothly, with little fuss. In all respects this appears to be a simple, clever and long lasting arrangement.