We GK Group is a Group company, and we have our own factories separately in producing Protective devices, circuit breakers,switches,relays,transformers etc. Following is the detail of this type of arrester: Product Name: Surge Protective Device Place of Origin: China Specifications: 1) Protection class: provides B 2) Composite type: 1P, 2P, 3P, 4P 3) Max. continuous operating voltage (Uc): 255V - 440V 4) Nominal discharge current (8/20μs) (In): 30kA, 40kA, 50kA, 80kA 5) Max. discharge current (8/20μs) (Imax): 60kA, 80kA, 100kA, 140kA 6) Voltage protection level (Up): 1.5kV - 3.5kV If you are interested at any of the above,pls feel free to contact us. My email is: joy(at)cnagk(dot)com Thanks and you are welcomed to our company at anytime.