They have a focal plane shutter with speeds of 1/500-1, plus bulb and time. They have a PC plug on the back, and will accept the Contarex magazine backs. They were fitted with different types of mounting flanges, depending upon the intended use, but never with regular Contarex flanges.
Production dates and quantities are unknown, but some examples have wind levers styled on the Bullseye, while others have later style levers. These cameras are not particularly rare.