This 3/16″ ball retainer is the genuine spare part for the Shimano Dura‑Ace WH‑R9170‑C60‑TU‑R12 rear wheel system. It ensures smooth engagement and reliable operation of the hub’s mechanism, delivering precise rotational performance. Precision Fit for Shimano WH and FH Series: Engineered to fit seamlessly into the ball cage of WH‑R9170‑C60‑TU‑R12 rear wheels, this ball retainer is also compatible with hubs like FH‑RS770 and models across the WH‑R9170‑C40, WH‑RX570, and WH‑RS700/RX700 series—ensuring cross-series consistency in function and durability. Durable Design for Long-Term Use: Manufactured using high-quality materials to meet strict OEM standards, this retainer is built to withstand wear and maintain precise ball placement within the hub under riding loads. It contributes to both smooth rolling and hub longevity. Easy to Replace and Maintain: Ideal for servicing older hubs or performing a full rebuild, this genuine ball retainer offers a straightforward replacement option. Its precise design means no modifications are needed—just install, grease and maintain your hub’s smooth feel. The retainer holds the ball bearings securely in place, ensuring consistent engagement in the hub gear mechanism. This helps maintain responsiveness and drive efficiency—whether accelerating out of turns or spinning on flats.