This instrument is manufactured in accordance with the SH/T0123 standard and is suitable for the determination of extreme pressure lubricating oil (such as gear oil). The method of use is: the sample is exposed to constant pressure and dry air at a certain temperature, and the test is 312 hours. By measuring the growth value of the kinematic viscosity and the change of the precipitation value of the sample at 100°C, the oxidation stability of the oil is expressed.