Abstract: A two-piece cap for a water bottle comprises a main cap which has an annular top disk formed with a depending central well having three levels, each of a slightly smaller diameter. The main cap skirt which depends from the periphery of the top disk has an upper cylindrical portion formed with a truncated internal screw thread which merges into a horizontal bead extending about 180.degree. around the interior of the cap and terminates in a reverse thread portion which extends upward to merge with the leading edge of the truncated screw thread. Below the upper skirt portion is a downward-outward slanted conical portion merging with a lower cylindrical skirt portion having an internal locking bead. A first vertical score line extends from the bottom edge of lower skirt portion to the upper edge of the slanted portion. A second vertical score line, spaced a short distance from the first vertical score line, extends from the bottom edge of the lower skirt portion to the top disk.

Abstract: A two-piece cap for a water bottle comprises a main cap which has an annular top disk formed with a depending central well having three levels, each of a slightly smaller diameter. The main cap skirt which depends from the periphery of the top disk has an upper cylindrical portion formed with a truncated internal screw thread which merges into a horizontal bead extending about 180.degree. around the interior of the cap and terminates in a reverse thread portion which extends upward to merge with the leading edge of the truncated screw thread. A first vertical score line extends from the bottom edge of lower skirt portion to the upper edge of the slanted portion. A second vertical score line, spaced a short distance from the first vertical score line, extends from the bottom edge of the lower skirt portion to the top disk. A plug having a closed bottom and a smooth exterior fits into the bottom of the well.