Hydro Flask bottles are perfect for the everyday and the big adventures. With double walled insulation, Hydro Flask bottles keep beverages cool for 24 hours and hot for 12 hours, whilst the pro-grade stainless steel prevents transfer of flavours and is durable enough for any journey. Hydro Flask bottles are also always BPA free. This Black colourway looks great and the 21oz size is the perfect mid-size for everyday use.