The stopper is a number 10 1/2 (ten and a half). The base just fits into the ring, and then it unscrews like butter. Like really warm butter, actually. Stopper is about $3, and should stay in your toolkit for the camera. Regards, -- Martin Melhus | PDGA# | Being politically correct means melhus@fdrc.iit.edu | 11296 | always having to say you're sorry.