Iridium spark plugs. The proposed set contains 4 spark plugs with a center electrode made of iridium wire with a diameter of 0.5 mm. The use of such material significantly increases the life of the plug. The diameter of the thread is 14 mm, the length of the threaded part is 19 mm. The ribbed surface of the insulator creates additional resistance to high voltage, preventing spark breakdown to the body. The metal part of the housing has a high-quality nickel coating, which guarantees that the plug does not "stick" to the engine housing.