GSP9 2Pole Surge Protector 20KA-40KA SPD AC275V AC385V 400V 440V SPD House Surge Protector 1P+N Din RailGeneralGSP9-C40KA series surge protection device (in short SPD,surge suppressor surge arrester)is suitable for TN-S, TN-C-S, TT, IT etc, power supply system of AC 50/60Hz. StandardIEC61643-1, GB18802.1.There is a failure release mounted on the module of surge protection device, When the SPD fails in breakdown for over heat and over-current, the failure rlease will help electric equipments separate from the power supply system and give the indication signal, green means normal, red means abnormal, it also could be replaced for the module when has operating voltage.Products features:1. Multi voltage choice: 275V, 385V, 400V, 440V, 500V...2. Pluggable module, easy for installation and maintenance3. High discharge capacity, quick response4. Double thermal disconnection devices, providing more reliable protection5. Green window will change when fault and also provide remote alarm control at the same timeIf you need replacement core, please kindly check below link, be carefully to choose correct voltage!