The 34 oz. Black AdNart Portable Cold Brew Coffee Maker is an innovative brewing method combining coarse coffee grounds . cold water . and a long steeping time. The resulting coffee is smooth . delicious . less bitter tasting . and can be enjoyed anywhere cold or hot. Brew your coffee . add some ice . sweetener and milk (or whatever you like) and you are ready to go with 34 oz. of coffee. The double wall insulated stainless steel and Tritan coffee carafe will keep your coffee cold up to 24 hours. If you put hot coffee in it will stay warm up to 12 hours.