RG-6 cable is one of the more common types of coaxial cables used for commercial and household purposes. The term RG-6 is a generic label that can be used to describe a whole range of cable designs. In fact, all cable designs described under RG-6 may well differ from one another in center conductor composition, dielectric type, or shielding characteristics. RG-6 was originally a military specification meaning Radio Guide, but this term has become obsolete due to lack of use. Today it is used to describe coaxial cables with 75-ohm impedance and 18 AWG center conductors.