Acer AR180 F1 - Manual (Page 140)

Appendix B: Rack mount configuration 122
Installing the system into the rack
Caution! To minimize the chances of injuries, make sure that two
or more people help in installing the server.
To install the system into a four-post rack
1 Confirm that the left and right inner rails have been correctly
identified.
2 Remove the inner rails from the mounting rails.
a
Extend the inner rail from the mounting rail until the rail
release latch clicks (1).
b Press the release latch (2) and slip the inner rail out. .
c Do the same thing to the other mounting rail.
Caution! To avoid personal injury, care should be taken when
pressing the inner rail release latches and sliding the component
into the rack.