Westinghouse 0252511 Fan Master Jr. Support Box, 13.4-Cubic-Inch Wire Capacity Fan Master Jr. Support Box can be installed on standard joists as well as wider joists where a saddle style box will not fit Wiring capacity on one side, the box can be mounted to either side of a ceiling joist without having to split the wiring Fits any ceiling fan up to 70 pounds or lighting fixture up to 150 pounds Electrical box measures 4 inches high by 1/2 inches deep; 13.4-cubic-inch capacity Includes Fan Master Jr. with Saf-T-Cap, Romex connector, and mounting hardware