HP D3000 Disk Enclosures - Manual (Page 28)

8. The rear ends of the rails have a CTO bracket that must engage with the enclosure in order
to secure it to the rails.
Align the CTO bracket to the corresponding rear slot into the chassis. The movable bracket
can be slid forward or back to correct position. The provided screw will secure the bracket
and chassis to the rail.
NOTE: The provided screw must be secured tightly. HP recommends using a T25 driver.
9. When cabling the device, use holes provided in the rear rack rails, install tie wraps, and route
external cable(s) as required.
28 Installation