Made with double-walled construction and high quality 18/8, food-grade stainless steel * Lightweight and perfectly sized to fit in most cup holders * Free of BPA, phthalates, lead and other toxins, stainless steel caps create 100% stainless interior * Can be used with the Klean Kanteen flip D-ring cap and the new cafe cap * Great for home, office, travel or even back country - works with standard water filter accessories