The inserts guarantee a low temperature in the portable refrigerator. The maximum cooling time is 12 hours . Please note that the effect depends on factors such as the external/air temperature, the number of inserts used, and the original temperature of the products. Recommended minimum number of inserts: 10 liter refrigerator - 2 pcs. 20 liter refrigerator - 4 pcs. 32 liter refrigerator - 6 pcs. Specification: Material: plastic Capacity: 2 x 400 ml Number of pieces in the set: 2 Dimensions of a single insert: 3 x 9.3 x 17.4 cm Operating temperature: -18°C to +45°C How to use: Before use, place the inserts in the freezer for at least 6 hours. Then, place them on top of the food being transported in the cooler.