The Ardent thermos by Waterline brand maintains the temperature of its contents for a long period of time - 24 hours. This heat retention is achieved by using durable high-quality food-grade SUS 304 stainless steel, as well as vacuum copper insulation between the double walls. The copper layer between the walls of the thermos allows it to retain heat slightly longer by reflecting thermal radiation (a small part of the total heat loss). Ardent has a very unusual lid with a matching cord, making the thermos even more convenient to use and carry, and it can also be hung. The lid is detachable: the cord can be removed for cleaning, and then placed back in its place. - Vacuum copper insulation, double walls made of SUS 304 stainless steel ensure long-lasting temperature retention for up to 24 hours. - Lid with cord for carrying is an interesting and functional detail. - Completely leak-proof. - Convenient universal volume of 500 ml.