SPD for Class III Feature: 1, low residual,low leakage current. 2,Response time ≤ 25nS 3, Thermal release /Fuse function, quickly,response. 4, Show normal/unnormal: turn green: normal: turn red:unnormal. 5,Can ad to telecomm and equipment. 6,Can be mounted on Th35 mounting rails. 7,Make mobile modular constrution ,installation and change are very easy. SPD for Class III