a molded plastic container and closure is provided with a double lock , the top lock being formed by the container rim and a protrusion on the inside of the closure channel . the bottom lock is formed by a segmented flange on the container sidewall and a second annular protrusion on the inside of the closure skirt . a zig - zag tear line allows the second lock to be removed thereby to create alternating areas of greater and lesser clearance between the newly formed skirt edge and a second , lower flange on the container sidewall .