I started using 25-32 tubes on my 700x28 tire but it would also fit easily in a 25. If that's what you have, use it. I bought 5 of them at once because that was the only way to get them a year ago when everything bike related was in short supply and I figure that I seem to go through tubes on a regular basis. Since I bought them though I've only had one issue and that was when I broke the presta core.