Lenovo THINKSERVER 3821 - Manual (Page 211)

13. Remove both of the backplanes from the 2.5-inch disk drive cage (see
“Removing a 2.5-inch disk drive backplane” on page 198).
14. If you are instructed to return the 2.5-inch disk drive cage, follow all packaging
instructions, and use any packaging materials for shipping that are supplied to
you.
Chapter 7. Installing optional devices and replacing customer replaceable units 203