The cap fits as it should on my Stihl 029. Everything about it is lower quality than. The whole body, threads and reinforcement is thinner and weaker than OEM. The cap split and started leaking after the second refill. My original caps lasted over 25 years, these lasted 24 hours. Just get oem replacements. Usually oregon stuff is pretty good so didnt think I would have an issue but side by side comparison its easy to see how much lower quality these are.