Hydro Flask 18 oz Wide Mouth Vacuum Insulated, Stainless Steel Water Bottle Double wall vacuum insulated stainless steel water bottle keeps drinks cold for up to 24 hours and hot for up to 6 hours Premium grade 18/8 Stainless Steel BPA free Sports Bottle High quality colorful powder-coated matte finish exterior that never sweats The Lifetime Warranty make Hydro Flasks the best water bottles