Wilwood Narrow DynaPro four piston radial mount calipers combines the versatility of radial mounting with a sleek profile, superior strength, and extreme durability in adverse conditions. With an overall weight as light as 3.58 pounds, the DynaPro has become a favored choice for a broad range of sports, rally, and off-road driving applications. The strength of the DynaPro is a combination of process and design. The process of stess-flow forging re-aligns the internal grain structure of the metal to flow within the contour of the caliper body. This produces a part with superior strength over machined block billet parts or castings. The FEA generated body design features a radial transition between the piston bores and caliper bridges. This eliminates macined steps and shoulders in this critical strength area and substantially increases the resistance against deflection and body separation under high load. Structural deflection and volume displacement testing have proven the efficiency of this innovative design. The bottom line is a firm pedal with outstanding stopping power. The Narrow DynaPro fits rotors up to 12.19” feature heavy wall stainless pistons to provide addition protection against corrosion and heat transfer from the pads. All DyanPro calipers can also be optioned with Thermlock pistons for maximum thermal protection in sustained high-heat applications. The DynaPro incorporates other exclusive Wilwood performance enhancements. Stainless SRS bridge plates eliminate caliper bridge wear from pad gouging while dampening noise and vibration during engagement. Internal fluid passages eliminate the need for external crossover tubes and four corner bleed screws allow effective gas evacuation regardless of mounting location.