Klean Kanteen Stainless Steel Flip D-Ring Cap for Wide Kanteen Bottle 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 Multifunctional-can be used flat or as a loop for leak-free hydration on the go