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Fine wire center electrodes come under a variety of names depending on manufacturer, IE - Tapered point, Ultra-Fine electrode, Taper cut electrode, Necked down electrode. Originally designed to improve starting and reduce fouling in two-stroke engines, this design was found to improve performance in four-stroke engines as well.

All operate on primarily the same principle, a spark plug with a fine wire electrode will perform better than a traditional plug. There are two reasons for this, first is because a smaller center electrode requires less voltage to jump the gap. This means fewer misfires, which should be seen in higher mileage and more horsepower. The second reason is smaller center electrodes reduce quenching. The smaller center electrodes have required exotic metals such as platinum or iridium so that they can still maintain (and usually surpass) the longevity of a traditional spark plug.

Currently the finest wire performance plugs available are made by Denso at 0.4mm diameter (image 1), by NGK at 0.7mm diameter (image 2), and by Champion at 1.1mm (image 3), a traditional center electrode is typically 2.0 to 2.5mm (image 4).