Arlington Industries FB443 1/2 and 5/8-Inch Drywall Fan and Fixture Mounting Box, 1-Pack Made in USA L-shaped fan/fixture mount securely to single or double joists, unit is 17.96-cubic-Inch Shipped in place screw allows for a quick and easy installation Locator posts assure proper positioning of fan or fixture bracket No loose parts to misplace, all pieces are integrated into single unit