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 and vacuum copper insulation between the double walls. The copper layer between the walls of the thermos allows it to retain heat a little 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 a cord for easy carrying is an interesting and functional detail. - Completely leak-proof. - Convenient universal volume of 500 ml.