Today I took out my 135W film back for my SQ-A. With the matching 135 screen, it is a pleasure to use it. The only thing is that, this back works like a real 135 camera, not a Bronica back. When I wind the film, it won't automatically get to frame 1. I'll need to expose 2-3 frames before reaching frame #1. Then the camera would fire even with dark slide inserted. I wasted one or two frames because of this. I still need to get the film processed before I can comment further.