A high voltage surge protection device having a characteristic impedance includes a center conductor defining an axis, an electrically conductive outer body concentrically disposed in surrounding relation to the inner conductor, and a dielectric layer disposed between the center conductor and the outer body. An electrically conductive surge protective element having a first value of effective impedance is disposed in electrical contact with the outer body and in spaced-apart relationship with the center conductor. The spaced-apart relationship forms a gap between the surge protective element and the center conductor. An insulative tuning element having a second value of effective impedance larger than the first value of effective impedance is coupled to the surge protective element in impedance-restorative relationship. The combination of the first value of effective impedance and the second value of effective impedance effectively equals the characteristic impedance of the high voltage surge protection device.