Yesterday I bought a Nikon EM, and assorted equipment. Ok, really I bought a 24mm 2.8 Nikkor, and there was an EM attached to it. Anyway, among the assorted odds and ends in the box was a tiny cap, slightly larger diameter than a nickel. It says Nikon on it, and also says EE. Google hasn't helped, the EM manual didn't seem to mention it, and I can figure out what it covers. Anyone?