HP SureStore E Tape Library Models 2/20, 4/40, and 6/60 - (English) User's Guide
Library Installation
Installing the Library into a Rack
Chapter 11-22
8. Open the tape doors and tighten the screws to secure the library into
place (Figure 1-14).
NOTE The doors may be key locked. The keys are attached to the power supply
handle on the back of the library.
Figure 1-14 Location of Securing Screws