ILSCO® Panelboard Stack Lug, Dual Rated, Series: PB, 2 AWG to 600 kcmil Conductor, 1/2 in Bolt/Stud Size, For Use With: Aluminum/Copper Conductors, 2000 VAC, 1-3/4 in Hole Spacing, 2 Ports, 1/2 in Hex, 5-11/16 in Length, 1-1/2 in Width, 3 in Height, Aluminum, Electro-Plated Tin