Provides up to 1000 cfm (cubic feet per minute) with 1 panel (sufficient for a 1500 sq ft attic). Galvanized steel construction. 18V (volt) thermally protected DC (direct current) motor. (5 year limited warranty on motor.) 13" high efficiency fan blades. Mounts behind any style of non-operable louvers. Includes: 12.6W multi-crystal solar panel with 25' power cord (10 year limited warranty on panel). This fan requires minimum 400 sq in (square Inch) net free air intake vent area. Additional solar panels available to increase CFMs.