WILSON: STAINLESS STEEL FLASK WITH CARRY HANDLE (500 ML APPROX). Double wall stainless steel vacuum insulation with food grade 304 stainless steel inside.Keeps your beverage hot for upto 8 hours and cold upto 12 hours.Removable middle cap for better cleaning and widen mouth. Rinse with hot/cold water before filling with hot/cold liquids for increased temperature retention