The StopTech Race Hardware Kit (89.000.0021) is specifically engineered for high-performance and competitive racing environments. This 8mm Drive, 8-Pin system ensures a secure and balanced attachment for 2-piece AeroRotor assemblies, allowing for essential thermal expansion and reducing rotor stress under extreme temperatures. Unlike standard street kits, the 'Race' version typically excludes anti-rattle spring clips to maximize cooling and mechanical response. Kit Contents (Per Rotor High-Strength Components): - (8) High-Tensile Drive Pins / Shouldered Bolts (8mm) - (8) Aerospace-Grade Self-Locking Jet Nuts / Hex Nuts - (8) Precision Hardened Washers - (8) Drive Bushings / Spacers Note: This hardware is designated for racing use only. One kit services one rotor assembly.