Small camera lens. Has f stops from f/2.3 to f/22. Not sure what camera it was made for, but says "WITTNAUR CHRONOSTAR". Threaded mount is 16mm diameter which is smaller than the standard "C" mount. Assembly is 30mm long and 28mm diameter. Has knurled iris adjustment. A real beauty!! One of our customers believes that this is the lens made for the Wittnaur Cine Twin 8mm camera/projector.