Arlington low cost, economical steel fan fixture bracket with plastic box delivers super secure, versatile on center mounting. Its steel bracket is fully adjustable to fit between joists spaced 16 to 24 in. The box is set for on center mounting but the 23 cu-in plastic box is positionable anywhere along bracket so you can place the fan or fixture where you want it on the ceiling. The FBR423 fan/fixture box delivers flush installation on ceilings up to 1-1/4 in THK. The bracket ends are pre-set for a 1/2 in ceiling. For other ceiling depths, simply bend the bracket ends along the appropriate score line engraved on the product.