Standard: GB/T18802.21-2004/IEC61643-21:2000 Nation Standard                                                                                                              Protection: 12~24V AC DC power                                                                            Features: Multifunction multilevel overvoltage protection, large max discharge current, low limiting voltage, quick reacting time, low insertion loss;                                                                                                                   Grounding Mode: Extension Line to ground;                                                          Design: Clear Logo, recognizable, aluminum shell, delicate size, easy installation