ActronAir Accurator Piston 0.0760" is a fixed-orifice expansion device for compatible R22 ActronAir refrigerant circuits, metering liquid refrigerant flow into the evaporator at the precise rate required for correct system superheat and capacity. The orifice diameter is critical -- fitting a piston with an incorrect orifice size alters system superheat and can cause liquid refrigerant to reach the compressor or starve the evaporator of refrigerant. Isolate power and recover all refrigerant before replacing any expansion device components.