2-1/8 in deep, 4 in octagon boxes with (4) 1/2 in side knockouts and (3) 1/2 in and (2) 3/4 in bottom knockouts are used to install ceiling and wall lighting fixtures, fans, convenience junction boxes and devices. Garvin Industries deep, octagon boxes are made with a versatile combination head screw. They also come with labor saving installation and mounting tabs that align with most lighting fixtures. GARVIN® Box, (4) Side, (5) Bottom Knockouts, (4) 1/2 in Side, (3) 1/2 in and (2) 3/4 in Bottom Knockout, Octagon Shape, Steel, G60 Galvanized, 3.55 in W x 2.125 in D x 3.55 in H Dimensions