The 9mm M9FS Beretta is a small guns weapon can be dual-wielded in Fallout: Brotherhood of Steel.
The 9mm M9FS Beretta was created in 1975 by the Fabbrica d'Armi Pietro Beretta, military adopted in 1985 and officially entered service in 1990. It's a short recoil, semi-automatic, single-action/double-action pistol using a staggered box magazine of 15 cartridges caliber 9mm. It provides good accuracy up to 50 m and it's also easy to clean.
The single version is good for the beginning but bad after Chapter 1. The dual variant is a very good weapon until the end of Chapter 1.