Stealth Girl

Stealth Girl is a perk in Fallout: New Vegas given by Lily if she is your companion. You may obtain Lily as a companion during the Guess Who I Saw Today quest.

Effects
This perk increases the stealth boy's duration by 200% while also granting sneak attack criticals an extra 10% damage.

Lily is located in Jacobstown.

This perk makes a single stealth boy last for 6 minutes, this has a great synergy with it's other effect, increasing sneak attack damage. Any sneak-based character would benefit greatly from the perk.