This product is either discontinued or we cannot get that from suppliers.
Qnap Controller Fru For CTL-ES1640DC-V2-80G-FAN-BBU, 160GB, NAS Accessories, ES1640dc v2 (160GB version), Controller FRU for ES1640dc v2 160GB, including FAN and BBU.
Qnap Ctl-Es1640Dc-V2–80G-Fan-Bbu Controller Fru For Es1640Dc V2 160Gb, Including Fan And Bbu.