Belt Drive Whole-House Fans •   Fan motor is attached to blade with a pulley for quieter operation     than direct-drive models •   Made with a rubber-mounted, self-aligning, precision ball bearing     drive assembly to reduce friction •   Two-speed operation, with a convenient wall-mounted switch •   An enamel steel housing with a powder-coated finish makes     than direct-drive models them extremely durable •   Sizes: 30" and 36" •   Shipped in an assembled wood frame to simplify installation