Acer Altos R5250 - Manual (Page 136)

Appendix B: Rack mount configuration 118
5 Attach the CMA (cable management arm) to the rear of the server.
The CMA allows you to tie-wrap all cables to and from the system.
As you slide the system in and out of the rack, the CMA collapses
and extends, keeping the cables untangled and attached to the
system.
(1) Insert the smaller CMA extension into the rear of the left inner
rail (A1).
(2) Insert the larger CMA extension into the rear of left mounting
rail (A2).
(3) Insert the CMA extension connector into the rear of the right
mounting rail (B1).
(4) Insert the CMA arm connector into the plastic cutout on the
CMA extension connector (B2).
(5) Attach the cable clips into the appropriate mounting holes in
the CMA (C).