It's a two-layer bag. The inside is made of black commando cloth. The outside is made of black Nylon. There are two zippers with double pulls that can be opened from inside or outside. (e.g. You unzip the bag from the outside, put your stuff in, put your arms through the holes then zip closed from the inside.)
The outer layer is the one that is dusty, musty and moldy. It is kind of rubberized but it's not brittle... yet.
The idea here is to have something on-hand for emergency use. Every once in a blue moon, you have to do a film-ectomy. Either you have to get the film out of the camera when the tail comes off the spool or, maybe, you have a malfunction or something. Being on the road, I'm not guaranteed to have a safe place to do that. Having the changing bag is basically a C.Y.A. measure.
Because the bag needs attention, that's the reason I put it away. I was probably going to need to buy another one anyway. But, since I'm going on a trip, I thought it would be a good thing to pack along, just in case.