No surprise, but Aurora has a ban on the books: Sec. 29-43. - Unlawful use of weapons. (a) A person commits the offense of unlawful use of weapons when he knowingly: (1) Sells, manufactures, purchases, possesses or carries any bludgeon, blackjack, slingshot, sand-club, sand-bag, metal knuckles, throwing star, butterfly knife, nunchaku (which shall be defined for purposes of this subsection as an instrument consisting of two (2) or more sticks, clubs, bars or rods to be used as handles, connected by a rope, cord, wire or chain, in the design of a weapon used in connection with the practice of a system of self-defense) or any knife, commonly referred to as a switchblade knife, which has a blade that opens automatically by hand pressure applied to a button, spring or other device in the handle of the knife; or a ballistic knife, which is a device that propels a knifelike blade as a projectile by means of a coil spring, elastic material or compressed gas; or