Transfer coolant to complete engine cooling cycle, maintain 100-150kPa system pressure, prevent boiling, withstand temperature difference of -40 ℃ to 120 ℃, resist vibration and coolant corrosion. Quality: EPDM material, wall thickness of 3-5mm, sealed interface, 200kPa pressure holding without leakage.Transporting coolant to build a heat dissipation loop, prevent pressure leakage, and resist cabin temperature vibration and chemical erosion. Quality: Made of EPDM/silicone, resistant to high temperatures up to 150 ℃, with interface fitting clamps, tested for no cracks or leaks, and meeting elasticity standards after aging.