The price is primarily driven by insulation performance and temperature control technology. You should prioritize boxes with High-Density Polyurethane (PU) foam or Vacuum Insulation Panels (VIP), as these materials significantly extend the cold chain duration. Additionally, ensure the box includes PCM (Phase Change Material) ice packs rather than standard water-based gel packs, as PCM provides precise temperature plateaus (e.g., 2°C to 8°C or 20°C to 24°C) required for different blood components.