The medium sleeve can be used on the large bell, this is how I use mine and it has lasted around 3 months so far. Have you looked underneath the cardboard inlay inside the box for the extra condoms, this is how they are being sent now from what I recall in an earlier post?
The large sleeve is too big for me, but the medium bell is too small. I am using the medium sleeve on the large bell. Will this ruin the sleeve?

