Made from high quality 18/8 food-grade stainless steel, the Classic is safe and toxin-free, and doesn't retain or impart flavors. No matter how many times it is filled, or what is put into it, the Klean Kanteen bottles keep drinks fresh and clean tasting. With a variety of cap options (sold separately), tailoring a Classic to your lifestyle is effortless. The 44mm mouth opening is easy to drink from and is large enough for ice cubes and bottle brushes (for extra thorough cleaning). The slim design of this 800ml bottle will fit in most cup holders and many bike cages.