The Iron Flask 2.0 is Here to Insure You Have the Hydration Needed to Get You Through the Day and Crush it! #yougotthis. The 2.0 version is leak proof with a rubber bottom that makes it non-slip and noise proof. It features 18/8 Stainless Steel and is vacuum insulated to keep your tumbler condensation free. The powder coated exterior finish offers durability and an easy grip. Icy beverages stay cold up to 16 hours & hot beverages preserve their temperature for up to 4 hours.