Accuracy on PK Models up to ±0.015% of Indicated Reading (Depending on Model) Pressure Range 4 H2O to 30PSIG Economical Self-Regulating Pressure Standard Exceptional performance and safety built-in floating ball operation, self regulating, rugged ceramic measuring ball, non-ceramic measuring ball, non contaminating test fluid, closed cover operation, ball valves for inlet and outlet, interchangeable weights NIST Traceable > Each Unit Includes Stainless Steel Weights Certificate of Calibration Case Instruction Manual