- SWELL. 14000-B20-65201. FILTER CAP. The Filter Cap lets you enjoy fresh-tasting tap water, wherever you bring your S"well! Simply fill from the tap, secure the cap, and sip for instant filtration. This leak-free cap features a protective cover and an ergonomic drink-through spout. Our premium carbon filter meets NSF standards to reduce chlorine and particulates, while improving taste and odor. The S"well Filter Cap fits our 9oz and 17oz Original bottles and comes with one filter.