When selecting a medical insulin pen box, the primary focus must be on temperature control and insulation performance. For passive cooling boxes, look for high-density EVA or Oxford fabric outer shells combined with aluminum foil or pearl cotton lining for thermal reflection. The gel ice packs included must be non-toxic and leak-proof, capable of maintaining a temperature range of 2-8°C (36-46°F) for at least 8 to 24 hours depending on the travel duration. For electronic versions, ensure the presence of a high-accuracy NTC temperature sensor and a clear LED/LCD display for real-time monitoring.