This product is either discontinued or we cannot get that from suppliers.
Transcend 512GB, External Portable (TS512GSJM500), micro USB to USB Type A, USB 3.1 Gen 1/Thunderbolt 10 Gb/s, Read up to 440 MB/s, Write up to 300 MB/s.
Transcend 512GB SJM500 Portable SSD For Mac External Portable (TS512GSJM500) Transcend's StoreJet 500 is a portable solid state drive specifically designed for your Mac.