Surge/Lightning Arrestor, Commercial Application, Made In Usa, Silicon Oxide Varistor Material, 100000 A Maximum Surge Current, Nema 4, 1 CT;18 PK Package Quantity, 2-1/4 In Dia. X 4-1/2 In H Size, 8 X 20 Microsecond Wave Shape;Response Time One Milliamp Test 5 Nanoseconds Special Features, Ansi Ieee Nema Standard;Nec Article 250 Standards Met, 3 PH Surge Arrestor Suppressor Type, 125/250 V Ac Voltage Rating