Product review (5 stars): The Orifice Worked perfectly
This product was needed for the proper performance of the Aprilaire 4040 - Humidifier 24v water solenoid valve.  It worked perfect.  I placed the orifice in the outbound opening of the new valve - the narrow tip up to fit into the copper tube. If you are reusing the copper tube with the old valve, you must remove the old orifice from the tube before connecting the tube to the new valve.  When I connected the copper tube to the new valve and turned on the valve, the water flowed properly to my humidifier.