Please install surge protector within 1 meter from device protected. The closer, the Better!!To prevent Routers and other connection equipment being struck by lightningTo prevent the notebook being struck by lightningWith 8 Lightning protection tubeProtects your Ethernet device from the damage of lightning & surge.Easy to install. Install between Ethernet and the protected deviceConnectors: RJ-45Material: shielded aluminum alloyDimensions: (L*W*H)43*13*15mmPackage includes:1pcNote:Size for manual measurement, there may be a 0 to 2 cm error, belongs to the normal phenomenon.