These end caps are designed for Zipp ZM2 hubs to ensure compatibility with 15x110mm Boost spacing. They are critical for achieving a secure, rigid connection between the hub and the fork, particularly for mountain bike applications. Model Compatibility: Designed specifically for Zipp ZM2 hubs. Material: Engineered from premium-grade, corrosion-resistant materials for durability in harsh trail conditions. Torque Cap Version: A version with a larger 31mm interface is available for enhanced stiffness when used with compatible RockShox forks.