Denso Iridium Racing Spark Plug IRE01-32 / 5721 Replace 0000-10-R105 R6725-105 Iridium Racing plugs are ideal for racing & tuned-up engines. Because racing engines do not have standard specifications it is important to select the appropriate plug type. Generally, electrodes that project into the combustion chamber have better ignitability & better performance. However, because of more exposure to high temperature combustion gases & as the ground electrode becomes longer, heat resistance & durability decrease. The higher the level of tuning, the greater the need to use a less projecting type. As the level of tuning increases, so does the need for a higher heat range.F1 technology Ultimate acceleration High reliability Boosted performance DIMENSIONS: Height (mm): 25 Width (mm): 25 Length (mm): 92 If you are unsure as to whether this is the correct part for your vehicle, please don't hesitate to contact us. Alternatively please use the cross reference table above.