Abstract: A portable device for measuring the refrigerant pressure in an automobile air conditioning system and, if needed, charging the system with additional refrigerant, is provided. An actuator is coupled to a pressurized container that selectively opens the container valve. A hose is provided, the first end of which is connected to the actuator, and the second end is coupleable to a service port of an automobile air conditioner. A T-connector with a check valve is disposed in the hose, and a pressure gauge is connected to the T-connector. When the second end of the hose is coupled to a service port and the actuator is not activated, the pressure gauge measures a pressure of the air conditioner. When the second end is coupled to a service port and the actuator is activated, refrigerant is released from the pressurized container and into the air conditioner.