What the middle icons stand for?

[bidoof01]

http://imageshack.us/photo/my-images/259/img0451u.jpg/
I know far left is wifi and far right is brightness but not sure in middle so I turned it off.

 

[dimachka]

GPS location services. And to the right of that is sync, you probably want that on too.

 

[anthony2558]

That's your GPS

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[forkball316]

GPS.

 

[DroidXcon]

From left to Right

Wifi..Bluetooth..GPS..sync...brightness

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