Simple question on a widget

[Krak-a-Lakn]

OK, I've tried to find this listed in the user manual (PDF) but no luck.
The Nexus one has a default widget that is has 5 boxes with a green bar. I understand most of the functions based on the icon (bluetooth, wifi and brightness) but 2 of them have me stumped. What does the one in the middle do ( to the right of the bluetooth icon)?
Then the is a refresh icon (second from right). What does this do?
I've played around with them but nothing seems to happen?

 

[Duvi]

The first icon is for turning WiFi on and off
The second icon is for turning Bluetooth on and off
The third iconis for turning GPS on and off
The fourth icon is for turning automatic email/contacts/calendar sync on and off
The fifth icon is for setting the brightness level of the backlight

 

[Krak-a-Lakn]

Thank you!

 

[Duvi]

No problem! Glad to be of assistance.