Hard urethane foam insulation, which doesn't use electricity, effectively maintains heat. The inner container uses molybdenum-containing stainless steel, which is resistant to acids. Stackable for storage. Durable and clean stainless steel body. Rice保温 capacity (approx.): 5.7L (for 3.2 sho) Heat retention (6 hours): 78°C or higher Size (width x depth x height (cm)): 43 x 36 x 31 Materials: Body/Stainless steel Lid/Inner container/Stainless steel Shipping will be in simple packaging. There are stains, scratches, and cracks due to long-term storage. It appears there is sand inside the lid. Sold as is, please understand.