Dell PowerEdge C6220 II Mise En Route page 8

4 On each vertical rack flange on the back, put two screw bases into the
two square holes right above the rail. See Figure 3.
5 Install the chassis stabilizer shipping brackets (optional) on the back
rack flanges.
6 Install and tighten the screws.
NOTE: To transport systems already installed in the rack, ensure that the two
chassis stabilizer shipping brackets (optional) are in place.
Figure 3. Installing the Chassis Stabilizer Shipping Brackets
Getting Started With Your System | 6