The power filter is connected to the power input of the instrument and equipment to attenuate the noise interference from the power line and the interference between the power line and the ground. The transient surge voltage induced by the power distribution system and the backrush caused by the load side etc. can be superimposed on the lines or simultaneously applied to the power line and the ground. It can pass through the power part of the instrument and equipment to the system power supply, which is the main cause of instrument failure. Using power filters is the most effective way to suppress line interference, improve equipment reliability and prevent interference. The product shell is made of iron plate stretching and forming, with the characteristics of small size, high voltage resistance, large insertion loss, etc. It is widely used in computers, industrial control, switch power supply, various instruments, electronic scales, audio and other equipment. Users can customize special specifications of filters.