This is 473ml/ 16oz Revomax Stainless Steel Vacuum Flask, with 316L stainless steel as inner lining and 304 stainless steel as external lining. 

Elevate your thermos experience with a 316L stainless steel inner lining, offering exceptional durability, corrosion resistance, and superior heat retention, keeping your beverages at the perfect temperature.

It can keep warm for 18 hours and keep cool for 36 hours!