Mechanically, the cavity magnetron consists of a large, solid cylinder of metal with a hole drilled through the center of the circular face. A wire acting as the cathode is run down the center of this hole, and the metal block itself forms the anode. Around this hole, known as the "interaction space", are a number of similar holes ("resonators") drilled parallel to the interaction space, connected to the interaction space by a short channel. The resulting block looks something like the cylinder on a revolver, with a somewhat larger central hole. Early models were actually cut using Colt pistol jigs. Remembering that in an AC circuit the electrons travel along the surface, not the core, of the conductor, the parallel sides of the slot acts as a capacitor while the round holes form an inductor: an LC circuit made of solid copper, with the resonant frequency defined entirely by its dimensions.