When evaluating a Mini Ice Box, prioritize insulation thickness and material; high-density PU (Polyurethane) foam is superior to EPS for long-term temperature retention. For electronic versions (thermoelectric), check the cooling delta, which should ideally be 15-20°C below ambient temperature. Ensure the outer shell is made of food-grade PP (Polypropylene) or HDPE to meet safety standards. Additionally, verify the seal integrity of the lid, as a silicone gasket significantly extends ice life compared to friction-fit lids.