J&D Manufacturing's ES Shutter Fan is a durable agriculture grade exhaust fan perfect for barn and building peaks, greenhouses, warehouses, and more. ES Shutter Fans are available without a cord, or pre-wired with a cord and plug for "No Electrician Required" installation. Fans ship fully assembled out of the box so you're up and running in no time. FEATURES Available in 10″, 12″, 16″, 20″, 24″, and 30″ Smooth and quiet operation Comes fully assembled out of the box Models with cord have 3-prong plug and are pre-wired for 115 Volts. No electrician required High-efficiency aluminum shutters with tie bar to reduce shutter flapping and opening on windy days ROUGH OPENING 20.5” W x 20.5” H