Broan MHB4 Bathroom Ventilation Fan Includes one set of hanger bars with screws Hanger bar system is fast, flexible, and easy for all types of construction Captive fasteners keep nails in place - no handling needed Instantly set the correct mounting height and level the housing between joists with integral bottom locator tabs Infinitely adjust the fan housing between joists from a span of 16-inch to 24-inch with hanger bars