All-in-one solution no additional tools requiredReplaces lost R-134a refrigerant and oil in automotive AC systemFormulated with COOL BOOST technology to provide up to 18% colder airSystem-safe leak sealer additive seals common AC leaks in rubber hoses, gaskets and O-ringsEliminates moisture buildup and acid from AC system to help extend AC system lifeReusable push-button dispenser with gauge and temperature dial indicatorAlways use protective gloves and eyewearShake can well.Start engine and set AC to maximum cooling.Locate AC low-side service port and connect recharge hose.Depress the top button. Allow contents to flow into the AC.While charging, rotate can between 12 oclock and 3 oclock every two to three seconds while continually agitating (shaking) the can back and forth.Continue this process until the correct amount of refrigerant is charged into the AC system or the can is empty.When the can feels empty, hold it upside down for one minute to dispense remaining contents before removing from service port. DO NOT OVERCHARGE SYSTEM!