Boxes, General Purpose, Square, Appleton, Type: 4" with knockouts, 2-1/8" Deep, Welded, with green ground wire, Volume: 30.3 Cubic Inch, Sides Knockout: 8@1/2", 4@ Eccentric KO, Bottom knockout: 2@1/2", 2@ Eccentric KO, UL Standard: 514A, UL Listed: E2527