he double-layer thermos vacuum flask is designed to fit into car cup holders and backpacks. It has a double vacuum insulation system that keeps your drink warm for up to 7 hours. This coffee cup has long durability and is made of stainless steel, which means it can withstand shock and ensure that your drink is safe to drink. Also, it has a double layer and vacuum flask system. And it's an eco-friendly alternative to bottles and cups. These water bottles are perfect for daily use. Users can carry it with them and keep the portable hot drink cup in the side pocket of the backpack. It has the ability to carry both hot and cold liquids.