Octagon Outlet Box Covers: Application - General Ceiling Outlet; Shape - Octagon; Material - Steel; Box Diameter in inch - 4; Box Depth - in - 2-1/8; Capacity - cu-in - 21.0; Knockouts/Sides-Bottom - (2)1/2" (2)3/4 - (4)1/2" (2)3/4"; Mounting Hardware - Bracket, Wrap Metal Stud; Additional Information - Metal Stud Size: 2-1/2"-3-5/8"
Additional Info: Metal Stud Size: 2-1/2"-3-5/8"