Ceiling Box With 11-1/2" to 18-1/2" Adjustable Bar Hanger, 20 CUIN, 4" Diameter x 2-1/4" Depth, 3/0-4/0 Combination, 6 Integral Clamps, Grounding Lug & Screw Attached, Fixture Spacing For 2-3/4" & 3-1/2", Non-Conductive, Non-Corrosive.