The 12" internally braced turbine with base is a non electric alternative to ventilation. It uses the natural force of wind and air pressure to spin and vent out stale attic air (345 cfm at 5 mph winds, 544 cfm at 8 mph winds & 969 cfm at 15 mph winds). The color is mill and has patented dupont delrine bearings. It works on roof pitches 3/12 to 12/12 and has a 2 year limited warranty.