This product is either discontinued or we cannot get that from suppliers.
Qnap System Cooling Fan Module For SP-X79U-FAN-MODULE, Rack cooling unit, 2U, Compatibility TS-879U-RP/TS-1279U-RP/TS-1679U-RP/TS-EC879U-RP/TS-EC1279U-RP/TS-EC1679U-RP.
The TS-X79U Fan Module from QNAP is a replacement fan module for TS-x79 rackmount models.