The Ametek Model RK deadweight tester is a primary standard used to calibrate pressure and differential pressure gauges transmitters transducers recorders and controllers and can provide a reference in pressure in process control applications. The RK tester is NIST traceable and accurate to +/-0.05% using stainless steel weights. Repeatability 0.0005% of output reading. Range 1 to 50 PSI. Includes 7 weights ranging from 1 psi to 10 psi. (2-1psi, 2-2spi, 1-5psi, 2-10psi, 1-20psi.