Installing a ceiling fixture in an existing home means working blind - you can't get to the back side of the ceiling drywall to push a standard box into position. Standard new-work boxes need the attic side of the ceiling open to set and nail. Without a box rated for old-work installation, you're improvising with spacers and drywall anchors that won't hold a ceiling fan. 4-inch diameter, 2-1/2-inch depth provides the wiring space and mounting footprint for ceiling fans, chandeliers, and recessed light fixtures in standard residential construction. The B618R design is a tested old-work box that accepts the fan-rated fixture screws and bracket hardware that the fixture manufacturer specifies. Designed for installation through the fixture hole from below - no attic access required. The box ho Stocked at Crofton Lumber and Akron Lumber.