Apple iMac (21.5 and 27-inch, Late 2009) - Manual (Page 25)

Chapter 2 Life with Your iMac 25
Power port
Connect the power cord to your iMac.
Security slot
Attach a lock and cable to discourage theft (available separately).
® Power button
Press to turn on your iMac or put it to sleep. Hold down to restart your iMac
during troubleshooting.
Memory access
Your iMac comes with at least 4 GB of memory installed as two 2 GB memory
modules.
Z AirPort Extreme wireless technology (inside)
Connect to a wireless network using built-in AirPort Extreme technology.
◊ Bluetooth ® 2.1+EDR wireless technology (inside)
Connect wireless devices, such as the Apple Wireless Keyboard and Apple Magic
Mouse, Bluetooth mobile phones, PDAs, and printers.