Unbreakable, stainless steel, Easy grip, heat resistant handle, always Quality Assurance Guarantee. Want to keep it hot or cold for 24 hours, here's the deal. The Always Stainless Steel Thermos Flask. This flask has been crafted out of stainless steel to offer the best insulation and most importantly, for durability as it is unbreakable. It can be your great day-to-day companion as it keeps your drinks hot and cold for 24 hours.