The thermodynamic design of Mr. Gasket's flex fans provides ultimate air transfer at all rpm's, thus reducing drag and increasing horsepower. Two different materials, stainless steel and aluminum allow you to choose the type that best suits your requirements for the street or track. Made of aluminum, universal in design, 18 inch diameter, with an 8000- RPM limit. Styled with black center and clear anodized blades. Product Features:Thermodynamic designUltimate air transferReduces dragIncreases horsepowerStainless steel and aluminumIdeal for street or track800 rpm limit