Nikon cassettes
Nikon made three film cassettes for the F2 :

AM-1 for 36 frames, for use in a standard F2 body.

MZ-1 for 250 frames, for use in a MF-1 bulk film back.

MZ-2 for 750 frames, for use in a jumbo film back.

All these cassettes have an turn style opening that is shut when the camera back is opened.
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