Hubbell-Raco 1213B2 Bushing, Insulated, Grounding, Lay-In Lug, Threaded, Rigid/IMC Conduit, 3/4-Inch, 2-Pack Malleable iron construction insures mechanical protection for the raceway Zinc electro plated for corrosion protection Dual rated aluminum grounding lugs may be used with copper or aluminum grounding conductors 3/4 in. Trade size: ground wire #14 solid - #4 stranded