Quote Originally Posted by srs5694
I just did an eBay search and found two up for auction. Am I correct in interpreting the photo that they've got a two-part outer wall with an opening that forms a "door" when they're appropriately rotated, and that this rotation must be done by the camera, so they'll only work in certain cameras?
Yes, the AM-1 only works in the Nikon F2. There is another one that works only in the Nikon F. There is a third one that works only in the Nikon rangefinder. I don't think Nikon made any other 36-exposure size cassettes for their other SLR cameras.

Yes, your description of how they operate is accurate.