ILSCO® Panelboard Stack Lug, Dual Rated, Series: PB, 2 AWG to 600 kcmil Conductor, 3/8 in Bolt/Stud Size, For Use With: Aluminum/Copper Conductors, 2000 VAC, 1-3/8 in Hole Spacing, 4 Ports, 1/2 in Hex, 4.9063 in Length, 2.4688 in Width, 3 in Height, Aluminum, Electro-Plated Tin