Western Digital's Portable SSDs Get Capacity Upgrades: 4TB of TLC for $680
 

Western Digital markets portable SSDs under different brands, catering to different market segments. The flagships in each brand make use of of very similar platforms - a M.2 NVMe SSD behind an appropriate bridge chip. The industrial design varies from brand to brand to appeal better to the target market. The WD My Passport and SanDisk Extreme Portable SSDs are USB 3.2 Gen 2 (10Gbps) SSDs using an ASMedia ASM2362 bridge chip and a WD SN550E PCIe 3.0 x4 NVMe SSD. The WD_BLACK P50 and SanDisk Extreme PRO Portable SSDs are USB 3.2 Gen 2x2 (20Gbps) SSDs using an ASMedia 2364 bridge chip with a SN750E and a SN730E PCIe 3.0 x4 NVMe SSD respectively.

https://www.anandtech.com/show/16365...lc-for-680-750