Regulator duster (Fallout 3)

to retain a duster you need to have negative karma, you get them from bounty hunters chasing you

The Lawbringer Perk (accessible at Level 15) places the Regulator HQ on your map and allows to visit Sonora Cruz, the head of the Regulators. The Regulator Duster is a piece of armor that you automatically get from Sonora Cruz for joining up with the Regulators.

you can also get the the duste with positive karma by joining the regulaters with the Lawbringer Perk and join the regulators. lvl15