@tubetime ...and it all goes up to 2477 which is a whopping 24mm x 7.7mm and packs up to 1Ah which is six times the capacity of a CR2025. So... If your project demands 3V, but an e.g. 2032 won't last enough... at the expense of some height there are other single cell options. They are less common but they are almost as widely available as the more common ones.