OWC Mercury On-The-Go Assembly Manual page 19

PATA Enclosure Assembly Process
Remove the green bridge board from the anti-static protective
bag.
Place your 2.5" ATA hard drive on the green bridge board and
line up the pins exactly as shown above. There are 4 extra pins
that the edge connector does NOT cover - they are at the bottom
of the bridge card in this picture. Fully insert the pins into the
connector using gentle force and do not lift up on the drive
while doing this, you don't want to bend the pins.
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