"PLASTIC INSERT UNIVERSAL VENTURI TUBE IS DIFFERENTIAL PRODUCTING PRIMARY FLOW METERING ELEMENT USED TO ACCURATELY MEASURE WATER,AIR,GAS,ACIDE,ALKALIES,SLURRIES,ETC.,WHERE LOW HEAD LOSS WITH HIGHEST ACCURACY IS DESIRED; CORROSION RESISTANT LIGHT WEIGHT UNIVERSAL VENTURI TUBE IS MADE FROM FIBERGLASS REINFORCED POLYESTER THROUGHOUT"