noneThe product is applicable for circuits of AC 50Hz/60Hz, with rated voltage up to 380V, the maximum current 150kA (8/20us), operating response time less 25ns Display form windows colors indicating the protector working state (green normal, red trouble),response time <=25ns.It was composed of a base, a neutral cartridge chip and more cartridges. We can only change the cartridge chip when it reaches the end of their life. The other type is BLBY means (10/350) type; it has high discharge current, about 20 times than 8/20us type Surge protectors. function: a) Acoustic optic alarm b) Trouble tele-control contact c) Thunder counter d) Waterproof case e) Prevents overload and shorting f) the current will be flow into the ground safely in case of the voltage fluctuation