GReddy Iridium Tune JIS#8 Spark Plug SpecificationsMade in Japan by GReddy these cold spark plugs have been specifically designed to operate at higher temperatures helping to disperse heat inside the cylinders. This improves combustion overall performances and engine reliability reducing the risk of knocking.Particularly adapted to sporty and tuned Japanese engines or for intensive use they are fully compatible with the following engines :Toyota : 4A-GE 4A-GZE (Corolla MR-2...)Nissan : CA18DET (S13)RB20DE RB20DET (Skyline R32 Laurel...)RB26DETT (Skyline R32 R33 R34 GT-R)Mazda : B6-ZE BP-ZE (MX-5 NA & NB)As well as certain European models : Audi BMW Porsche Renault Volkswagen...