Wilwood Hat-BB Front Brake Rotor Hat 2.8 In Fixed Mount 0.875in Offset 170-10149 GT Series Big Brake Short Offset hats are precision machined from premium aluminium alloys for high strength and attention to minimized weight. Hats in this category feature threaded rotor mount holes for use with standard through-hole mount rotors. Threaded hole hats may also be used with T-Nuts or bobbins designed for use with specially machined slotted hole dynamic mount rotors. When used in conjunction with matched Wilwood rotor hardware kits, GT hats provide solid, reliable performance in the most demanding conditions. Short Offset Hats are for narrow space applications with offsets often less than 1.00". They are available for most rotor bolt patterns in a variety of four and.