Robinair 75260 Coolant Refiller with Air Lock Preventer Robinair's Coolant Refiller uses a compressor powered vacuum to completely fill vehicle cooling systems in seconds without creating troublesome air bubbles Vacuum opens the thermostat, eliminates air in the system, then fills cooling system, including heater core, completely - no bleeding required Use to determine cooling system integrity by checking for system leaks under vacuum Universal, fits-all cone adapter works with any radiator or overflow bottle filler neck, eliminating the need for adapters Built-in gauge protector protects against inadvertent damage; tool includes clear hose, filter, and instructions