TheExhaust Fan with Shutter is a durable agriculture grade exhaust fan perfect for barn and building peaks, greenhouses, warehouses, and more. Shutter Fans come pre-wired with a cord and 3-prong plug for "No Electrician Needed" installation. Fans ship fully assembled out of the box so you're up and running in no time! Exhaust fans are usually positioned in a high location in the back wall. 12" is recommended for RIGA 2, 3, 4, Junior Victorians, Victorian VI 23-24 greenhouses16" is recommended for RIGA 5, Victorian VI 34-46 greenhouses20" is recommended for all RIGA XL greenhouses FEATURES 18-gauge heavy-duty galvanized housing Sealed and protected capacitor Rough Opening:12" - 12.25"x12.25"16" - 16.25" x 16.25"20" - 20.25" x 20.25" Power: Voltage: 115 Vac 60 Hz, Amps NP: 1.42A Smooth and quiet operation Comes fully assembled out of the box 3-prong plug and pre-wired for 115 Volts. No electrician needed for install! High-efficiency aluminum shutters with tie bar to reduce shutter flapping and opening on windy days This industrial exhaust fan is perfect for garages and other work spaces where you want some airflow Fan Guard:Meets OSHA 1910.212(a)(5) requirements to mount at any height on inlet side of fan (shutter side should be 7' above ground)StrongCoated steel for easy cleaning Fan Prop:Balanced3-bladedCorrosion-resistant coated steel hub Shutter:High efficiency aluminumFortifying ribs for added strengthTie bar to reduce shutter flapping and opening on windy days Motor:High efficiencyFully enclosedMaintenance-freeDirect drive Optional Thermostat and motorized air intake vent can be ordered Financing Available Installation Instructions Exhaust Fan with Shutter Installation Instructions