This LAN surge protector is used to protect a Wi-Fi router connected with an ethernet cable to a cable modem 100 feet away. Lake other reviewer‘s I found that out of the box there was no continuity through the unit so I returned it for a replacement. The replacement passes a signal through. There’s no way of telling if the unit is doing its job of protecting from surges because there are no lights to indicate anything at all, so I guess that if it explodes or if it stops passing a signal and the router is still OK then it has done it’s job. Also, the screw securing the green ground wire cannot be an oval or flat head because these types of screws will dislodge the ground wire terminal when the screw is tightened.