The GAF Master Flow externally braced turbines are efficient, easy-to-install venting options for your roof. They allow heat and moisture-laden air to escape your attic, helping to extend the life of your roof. They are designed with upper and lower steel ball bearing systems for years of trouble-free operation. The adjustable base allows for installation on virtually any roof, from 2:12 pitch up to 12:12 pitch. Color: Silver.