DT Swiss XD Drive Ratchet EXP Freehub with End CapThe DT Swiss Ratchet EXP freehub system, especially when used with an XD driver body for SRAM cassettes, offers a lightweight and reliable way to engage and disengage the drivetrain. The "EXP" stands for "Easy to Replace Parts" and highlights the system's design for easy maintenance. This system is favored by riders for its smooth engagement, minimal rolling resistance, and ease of maintenance.