Aripy® Dead-weight tester (commonly referred to as a mechanical weight pressure gauge or primary standard) is the most precise reference instrument in the field of pressure measurement. Its operating principle is based on the physical law that pressure equals force divided by area. Weights positioned atop the piston-cylinder system constitute a precisely defined force source. By generating a specific (opposite) pressure within the pressure balance, the system achieves equilibrium: the weights and the free piston within the piston-cylinder system are suspended together, thereby producing an extremely high-precision pressure value at the test port.