Description Product Description. Racing plugs are designed for use in engines with increased power output due to racing, circuit running or tuning. Therefore, the shape of the plug differs from the standard plug specified by the manufacturer, and there may be a slight sacrifice in plug life and low-speed performance. (Racing plugs do not improve power output.) Points to note when selecting racing plugs. Select the appropriate type by checking the thread size, plug type and shape from the part number of the genuine plug or the plug currently being used. Select the relevant ignition part shape with reference to "How to select the ignition part shape". The heat value must be selected in consideration of the increase in combustion speed due to increased engine power and operating conditions, in order to keep the temperature of the plug's ignition part in the optimum temperature range. The engine performance will not be improved simply by increasing the heat value. The presence or absence of a resistor in the plug does not make any difference in performance, due to recent improvements in the performance of the ignition system. Conversely, the use of non-resister types may cause ECU problems in some models. For details on compatibility, please refer to the manufacturer's website. If you want more beauty items Shipping Express shipping We can ship the item together. Please check the shop as there are various other products. go to our shop Most of the items will be delivered in 2-4 weeks after it shipped out. We will carefully deliver using the packing material. Import duties, taxes and charges are not included in the item price or shipping charges. These charges are the buyer?s responsibility. Please check with your country?s customs office to determine what these additional costs will be prior to bidding or buying. Customs fees are normally charged by the shipping company or collected when you pick the item up.These fees are not additional shipping charges. We won't under-value merchandise or mark the item as a gift on customs forms.Doing that is against U.S.and international laws.