Abstract: A cap capable of being used to close off an unthreaded cylindrical member and capable of being removed after closing off the unthreaded cylindrical member is disclosed. This cap has a one-piece, generally circular, relatively flexible, relatively impervious, self-supporting body. It is made of elastomeric material, preferably rubber, and is shaped so as to include between about 2 and about 12 successive levels, each level having a larger diameter than the level before it. This multi-level cap is useful for capping water or sanitary systems during testing of the systems. The cap preferably has 3 levels which fit three different standard sized pipes, one pipe at a time.