A carrier includes a frame defining a first space configured to accommodate a first type of hard disk drive, and an adjusting mechanism slidably coupled to the frame. The adjusting mechanism is transitionable between: (i) a first configuration in which the adjusting mechanism is located outside the first space defined by the frame, and (ii) a second configuration in which the adjusting mechanism is located inside the first space, the adjusting mechanism and the frame cooperatively define a second space configured to accommodate a second type of hard disk drive different from the first type of hard disk drive.