... 5.8 years experience 3 Level Power-supply Module (4P,3P+NPE) surge protector for ac power 1. Third level protection2. install ... residual voltage, quick response, standard guide rail design, standard plug-in modular design, easy installation, simple maintenance, module degradation indication ... exit failure and recovery, do not affect the normal power supply. Technology Parameter:Model SY-B-20KA/4PSY-B- ...