I love Kodak Snap-Caps. All I used in the early 1990's. Could walk into B&H and pick up a box of ten, cheap. Must have had fifty of them at one time. Wish I had known they were going to disappear, would have held onto them. Found a box of ten in 2011 and snatched it up, and found 11 loose ones that I also bought. Haven't opened the box of ten yet, but the other 11 are always loaded with Tri-X or Double-XX. As others have mentioned, an easy way to put the cap back on is start at the felt opening, get the cap securely attached there, then run your thumb around the outer edge until you hear it Snap into place, ergo the name Snap-Cap.
Good luck.
Best,
-Tim