GUARD MOUNTED DIRECT DRIVE EXHAUST FANS 20"Diameter Fan These exhaust fans can be bolted directly to the wall. Guard mount exhaust fans are designed for low-pressure exhausting and cooling applications. 3 aluminum fan blades are enclosed in steel spiral wire guards for safety. Wire guards feature built-in mounting holes for easy installation. 120V, single phase motor is totally enclosed and permanently lubricated for long life, UL listed. Exhaust fans feature pull chain operation. Includes junction box for direct wiring. Note: Rough-in hole size is 1/2" (+/- 5/16) larger than fan blade size. Optional Wall Shutters available. Horsepower rating based upon maximum speed/load.