Despite the description, the Disc Unit does not make Arma shoot CDs at enemies... unless the CDs where you come from are covered in razor blades. Using the Disc Unit, Arma shoots out a blade disc that returns like a boomerang and hits any enemy on the way out or the way back, but not both. It consumes only 0.5 Ammo, which makes reloading time a minimal problem. Arma can act quickly out of firing, which makes it useful against fast striking enemies. It deals very low damage and Arma can only have 2 discs out at one time though, which can be troublesome for fighting stronger Enemies and Bosses.