This product is either discontinued or we cannot get that from suppliers.
Qnap TRAY-35-NK-BLK05 HDD Tray For TS-328 NAS Accessories, Black, System hard drive tray, Bay Compatibility 3.5".
The 2.5" Drive Tray from QNAP lets you install a 2.5" hard drive or solid-state drive into one of the 3.5" bays on their TS-328 3-Bay NAS Enclosure.