Noark Surge Protection / Protective Device (SPD), UL 1449, for type 4CA applications, U4 series, L-N / N-PE 20kA (8/20µs) UL nominal discharge current, 3-poles + neutral (3P+N) - 277Vac/480Vac voltage system (UL) rated voltage - MCOV (L-N) 440V maximum continuous operating voltage (Uc MCOV), DIN rail mounting (70mm width), equivalent to 1002753