ILSCO Power Distribution Block, Mechanical connection, Dual Rated, Aluminum material, Tin plated connector,mounting bolt/stud size #10 in, mounting hole spacing 3.375 in., UL 1059 Recognized, C22.2 No. 65-03, Copper/Aluminum Primary Conductor 500 kcmil - 4 Str, Copper/Aluminum Secondary Conductor 10 Sol - 14 Sol and 2/0 Str - 14 Str, 5 conductors, 15 ports/wireways, Drive Type Main 3/8 Internal Hex, Drive Type Tap 3/16 Internal Hex, rated for 600 V, primary color Black, 3 poles, 1 ports per pole primary, 4 ports per pole secondary,