This product is either discontinued or we cannot get that from suppliers.
Qnap Accessory SP-SSECX79-Tray 2.5 Hard Disk Drive Tray for SS-ECX79U-SAS Series, Black, FF Internal, Compatible Drive Bay Width 2.5".
This HDD tray comes with four black flat head machine screws for 2.5" HDD. It is designed to be used with 12-bay SS-EC1279U-SAS-RP, 18-bay SS-EC1879U-SAS-RP and 24-bay SS-EC2479U-SAS-RP.