This product is either discontinued or we cannot get that from suppliers.
Vantec HDA-259A, Hard Drive Mounting Kit, 2 x 2.5" Drive to 3.5" Bay, Device Size 2.5", Aluminum.
The aluminum Vantec Dual 2.5" to 3.5" HDD/SSD Mounting Kit lets you easily mount up to two 2.5" HDDs or SSDs up to 9.5mm thick in a single 3.5" drive bay.