This is a great design that keeps the drive both aesthetically pleasing and convenient to use. This cable, when not in used, can be tucked away in the groove that runs around the sides. There's no Thunderbolt port on the drive instead, it comes with a built-in Thunderbolt cable that's always attached to the drive. On its underside, there's small area of openings for the air to come in, and on the front, there's a little ventilation fan that only runs when the drive gets hot. This casing also works as the drive's heat sink. The My Passport Pro comes in an all-aluminum chassis that's sturdy and good-looking. Still, it's not huge and you can still carry it around quite easily. That said, the 4TB My Passport Pro is one of the bulkiest bus-powered portable drive on the market.
The 4TB version has more girth because it houses two 15-mm internal drives (2TB each), whereas the 2TB version houses two 9.5-mm internal drives (1TB each).
