Klean Kanteen Stainless Wide Mouth Loop Cap Fits all sizes of wide mouth and insulated Klean Kanteen bottles The 100-Percent stainless steel lining guarantees that no plastics ever touch your liquids The BPA-free polypropylene upper keeps the cap lightweight and durable Handwashing the cap is recommended Durable loop can clip to backpacks, bags, etc for hydration on-the-go