This pin says you're an official New California Ranger. Look -- it's got a code wheel and everything!
The Ranger pin is a miscellaneous item in Fallout 2.
The Ranger pin is a badge, showing you to be a member of the NCR Rangers. It is a white star with three stripes coming out either side of it.
- Elise will give the pin as a reward to the Chosen One for successfully freeing the slaves.
Sheriff Earl Marion in Redding comments on the Chosen One being an NCR Ranger if they have the pin in their inventory the first time they talk to him; however, this has no real effect on anything.