This Master Flow 12" aluminium rotary turbine is an internally braced roof ventilator made of aluminium with an octagonal aluminium base. It is an efficient, easy-to-install venting option 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. It can be installed on any roof with a pitch from 2:12 to 12:12. It is protected by a limited lifetime warranty from the manufacturer.