Feed-through filter, mainly used in metal panels, utilized to suppress the interference of high-frequency harmonics on signals, power lines and other filter pieces. Feed-through filter is used to install the metal panel of the feed-through filter, which has a very low grounding impedance, and the metal panel not only acts as the filter grounding but also plays the role of isolating the coupling between the input and output of the filter, so the feed-through filter has a very good high-frequency filtering effect.