I purchased this for a third party and they are very satisfied with the product.Works great to upgrade a NC 250 or NC 300 engine. I installed on a Trailmaster TM38 Dirt bike.I own three motorcycles. When it is time to change out the plugs, I always pay the extra money and buy Iridium plugs. They cost anywhere from $7-$10 each, so they are not cheap, but I want my bike running perfect and purring like a cat while riding a short distance through the mountains or taking off across country. No hassles, no problems. My bike starts first time, everytime, runs smooth, great mileage and no problems while away from home. So, are these worth the price difference? Because I ride about 20,000 miles yearly, I would rather pay the difference for idea plugs and enjoy worry free riding instead of possibly having a break-down somewhere far from home. They give me piece of mind. Money well spent. Buying NGK is a personal preference. I have used NGK in my street-bikes, ATV's and in my younger years I used NGK in my dirt bikes. I'm content with their performance and longevity.UPDATE: I just purchased my second set of these NGK CR8EIX plugs for my 2008 Yamaha FJR1300. They work great in my street bike, I also put them in both ATV's, my 2012 Yamaha WR450F and my Suzuki 650 Burgman. I prefer these plugs because they don't foul under any circumstances. I am replacing these after 24,000 miles in my FJR simply because I am preparing my bike for a long road trip, so regardless of how long they may last, I want new plugs for this trip. I consider it just one additional step in my preparation for a long road trip and don't want to have any interruptions of any kind. Cost, yes they are a few extra dollars, but so what. If you can't afford to run the best, perhaps you should consider changing your lifestyle! Do you pay a little extra for a better air filter, better tires, better riding gear, then don't sweat the small stuff, take care of your machine so it can take care of you!GoodSatisfiedI read a lot of stories saying there is a high chance to get a fake spark plugs if you're buying from Amazon and the likes. Got me somewhat worrying and curios, and so I went to an auto parts store and bought the same set of plugs.Guess what -- the set from the parts store is exactly the same as the one from Amazon. It looks exactly the same, all the dimensions are identical, the weight is the same, the resistance is the same.I have replaced a set which was installed 3 years ago and did 25000 miles on my Yamaha FJR1300, and it did not really need to be replaced.After making some changes to my RE Himalayan, I decided to go the iridium route to make sure any additional fuel was getting burnt. I wouldn’t necessarily suggest this to a stock motor, but adding a fuel booster, higher flow filter and exhaust, I wanted to make sure the spark matched the rest. I will note, if you think this won’t fit a Himalayan, remember that the cap can twist off for the smaller diameter connection needed for the stock wire.I upgrade to iridium and works great so far BMW Nine TI was surprised how much difference these plugs made as an uprade to the standard NGKs I had been using before (Yamaha XJ600S). Better cold starting, smoother running, improved throttle response, and a more powerful feel to the engine. It would be interesting to do some kind of A/B performance comparison, but the effect is certainly enough to be noticeable, whatever the measured difference might turn out to be.I'll need to go a few months before I get a clear idea of how they affect MPG (something I can and do measure), but on performance alone I won't be going back to standard plugs.Exactly what I need. A word of notice is that there is a small cap screwed into the top of the spark plug. You will need to remove it before inserting the plug into the chamber or it'll be a lot of work to take it out (ask me why I know).Used on YZF-R125 2014 works perfectly just remember to sake the cap off and use some copper greaseDopo varie tribolazioni, analisi di post su vari forum e ricerche su youtube ho finalmente comprato questa candela. Vorrei averlo fatto prima: a fronte di un costo poco più alto di una candel tradizionale la differenza si sente (soprattutto nelle ripartenze) e l'accensione è più sicura, anche nelle giornate fredde. Se la montate su una Royal Enfield Himalayan ricordatevi di smontare la capocchia con cui arriva (basta stringere con una pinza e ruotare per farla venire via) prima di montarla sulla moto, in quanto altrimenti la pipetta non riesce a fare bene contatto con la candela.Hai trovato questa recensione utile? Clikka qui sotto!I bought this plug for my single cylinder Honda MSX125SF and enjoyed marginal but noticeable better engine characteristics. I have used iridium-tipped plugs on other multi-cylinder motorcycles with nothing really changing, but on the 125 it really helped.One universal benefit I have found with all plugs of this type is that they do seem to last forever and never need re-gapping.