advice about xbee

Hi everyone.

I want to set a communication between two arduino using xbee, but I don’t know which model choose.
I would like to separate them 500 yd each other and I don’t know if it is better to use repeaters or xbees that reach long distances

What you advise me?

use xbee pro s2b with rpsma antenna
it can 1 km - 3.2 km out door

i have try it...