Remove unwanted moisture, odor, and fumes with high performance shutter fans from DURAFAN, J & D Manufacturing and Direct Drive. DURAFAN Select Speed Shutter Fans have built-in speed switches and come in sizes from 12" to 24". Variable Speed Shutter Fans have a heavy-duty, high efficiency motor that is designed to work in the harshest of environments. The DURAFAN Select Speed Shutter Fans are economical and versatile. The totally enclosed motor comes complete with built in speed switches and a 9' cord.