Apple iMac (21.5-inch, Late 2011) - Manual (Page 25)

25 Chapter 2 Life with Your iMac
Power port
Connect the power cord to your iMac.
Security slot
Attach a lock and cable to discourage theft (available separately).
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Power button
Press to turn on your iMac or put it to sleep. Hold down to restart your iMac during
troubleshooting.
Memory access
Install additional memory. Your iMac comes with at least 2 GB of memory installed as
one 2 GB memory module.
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802.11n Wi-Fi (inside)
Connect to a wireless network using built-in 802.11n Wi-Fi technology.