The Max-Fan?? Pro Series is even more efficient and stronger than the original Max-Fan?? design. The Max-Fan?? Pro Series has a much more robust housing due to the fiberglass reinforced plastic compounds that meet all of the UL and CSA requirements. The fans have three control speeds for true performance. These fans run quieter than the Max-Fan??. The fans come with the EZ Mountƒ?› bracket for easy mounting.