JPL-5 measures the content of wear debris content by using the principle of electromagnetic induction and the magnetic field change of the sensor coil caused by ferromagnetic wear debris content in the oil sample. It shows a good linear relationship with the iron filings content and particle size of the oil sample. It features high sensitivity, accuracy and repeatability. No sample pretreatment or organic solvents are required. It can accurately measure the content of ferromagnetic metal abrasive particles in various oil samples within a few seconds. The measurement results are directly expressed in actual concentration values (milligrams per liter or ppm), facilitating users' interpretation and analysis of the data.