This Master Flow 14" weathered wood aluminium rotary turbine is an internally braced roof ventilator made of aluminum with an octagonal aluminum base. It is efficient, easy-to-install venting options for your roof. It allows heat and moisture-laden air to escape your attic, helping to extend the life of your roof. It is designed with upper and lower steel ball bearing systems for years of trouble-free operation. The base is 22" in width. The overall height of the assembly is 20 13/16". It can be installed on virtually any roof with a pitch from 2:12 to 12:12. It is protected by a limited lifetime warranty from the manufacturer.