Mine has the simpler, fixed-focus Kodet lens. The shutter has one speed plus bulb, and there is only one aperture. Although the camera uses a red window to monitor film position, it is equipped with a mechanism to prevent double exposures.
My Duaflex is a good example of what happens when friends learn you collect old cameras. My partner at work found it in a shop for me. I’ve loaded it with a roll of FP4 for the week.