Abstract: A coupling sleeve has internal screw-threads for enabling the sleeve to be screwed onto an externally threaded neck of a commercially available small bottle of water or other liquid. External screw-threads on the sleeve enable it to have screwed to it a cap-and-nipple combination of a baby's drinking bottle. A first seal is provided between the neck-rim of the bottle and the sleeve and a second seal is provided between an end-rim of the sleeve and an annular sealing flange on the nipple.