The traditional height before USB SPI was ½ inches (12.7 mm), now there are heights between 5 mm and 15 mm, distributed ⅜ inches (9.5 mm) and ¼ inches (6.35 mm). What height is required depends on the device in which the drive is to be installed from. The interface connector is modified compared to the larger designs, the ATA, the distance of the pins is reduced from 2.54 mm to 2 mm.
There will continue to 4 pins (43 pins) that replace the separate power connector of the larger models. 2.5 inches hard drives require only one power supply at 5 V, and the need for a second operation voltage at 12 V does not apply to larger plates. 2.5 inches SATA hard drives have the same connections as the 3.5 inches drives, only the 5 mm high drives have because of the small space available, a special SFF-8784 connector.