Modified Nikon MF-3 Rewind Stop Film Back for the Nikon F2, F2S, F2SB, F2A, F2AS and F2T. This back attaches to the camera and used in conjunction with Nikon MD-1 or MD-2 Motor Drive. Normally, the MF-3 allows the motorized rewind to stop automatically as soon as the film leader becomes disengaged from the take-up spool, leaving a leader of film sticking out of the cassette. The modification was very professionally done as you can see. The back is in excellent shape with light signs of use.