Dell PowerEdge C6220 II Getting Started page 6

1 Push on the latch release buttons on the midpoints of the end piece to
open the rail latches. See Figure 1.
2 Align the end pieces of the rails on the vertical rack flanges to seat the
pegs in the bottom hole of the first U and the top hole of the second
U.
NOTE: The rails can be used in both square-hole (item 1 in the following figure)
and round-hole racks (item 2 in the following figure).
Figure 1. Pushing the Latch Release Buttons
NOTE: To remove the rails, push on the latch release button on the midpoints
of the end piece and unseat each rail.
Getting Started With Your System | 4