Made of 18/8 food grade stainless steel, no liner needed * No BPA, phthalates, lead or other toxins * Doesn"t retain or impart flavors for a clean, fresh drink every time * Rounded corners are easy to clean with no hard angles where dirt, germs or other bacteria can stick * New Sport Cap 30 made from BPA-free polypropylene ensures a smooth even flow of liquid with no "chirping"