Seraphin® heavy-duty provers are used for testing tank trucks, containers, testing tanks, and large-volume meters. Each of the provers has a bottom drain and a graduated neck and is made with exceptional accuracy and attention to detail. Seraphin® provers are an easy-to-use, reliable, and low-cost method of measuring the output accuracy of liquid metering equipment. All of the provers are manufactured using type 300 stainless steel and are corrosion-resistant over an indefinite period of time (exceeding several decades). Seraphin® heavy-duty provers are designed, manufactured, and calibrated to the latest OIML R-120, Measurement Canada, API, and NIST handbook 105-3 standards and are the industry standard for heavy-duty provers.