Abstract: This invention refers to a cap capable to be screwed in with nipple and cover cap which allows that refreshment or water bottles which have a conventional screw thread system can be used as baby's bottles. Its characteristics are: a cap (observe FIGS. 1. 2 and 3) which it joins to, by means of a continuous thread system (3), in its inferior part, a bottle with ring neck; its superior mouth has a surrounding extension which stands out the raised edge (1), this mouth has a central perforation (2) which allows passing a nipple through (see FIGS. 1, 2 and 4); it also has surrounding lug in its internal superior part which is used as a tie (4) this makes the adjustment to the inferior extreme (7) of the nipple when it passes in, the bottle and nipple are joint together by the cap capable to be screwed in. In like manner a cover cap has been adapted (see FIGS.