MIL-PRF-62028B, PERFORMANCE SPECIFICATION: HOSE, AIR DUCT: HIGH-TEMPERATURE, FLEXIBLE, REINFORCED (30 OCT 1995) [SUPERSEDING MIL-H-62028A]., This specification covers reinforced flexible hose used for transferring heat to crew compartments and preheating engine compartments, oil pans, batteries, fuel and coolant lines, and other components to assist in starting engines under extreme cold weather conditions (see 6.1).