Grand National GN4R forged aluminum four-piston radial mount calipers bring current state-of-the-art design, materials, and manufacturing technology to this long standing icon in the Wilwood caliper line. With a High-strength forged aluminum body in a hard-anodized finish and Purpose built for rotors with a 1.25” thickness and a special bracket offset. Also these calipers come with Thermlock® insulated pistons.