The model BL513 water deadweight testers are applicable oil-free pressure calibration and measurement solution. The oil-free test performance of BL513 is much better than other solution of hydraulic piston gauges plus oil-water separator. Deadweight testers are used as basic primary standard and its principle is accepted all over the world for the most accurate pressure measurements. No other piece of equipment for pressure measurement can match the stability, repeatability and accuracy of the piston gauge.