B10 paper is the smallest size in the B series of paper sizes defined by the International Organization for Standardization (ISO 216). Its dimensions are 31 mm × 44 mm, which is roughly equivalent to 1.2 in × 1.7 in. The B10 size is sometimes used for business cards and other small items, but it is not as common as the A series paper sizes.
One notable difference between B10 and the larger B sizes is that B10 is not a geometric mean of A series paper sizes. Instead, it is a proportionally reduced size of B9 paper, which is half the size of B8 paper. This means that B10 paper has the same aspect ratio as the other B sizes, but its dimensions are not directly related to the A series.
Due to its small size, B10 paper is not commonly used for general printing or document creation. However, it is useful for small notes, reminders, and business cards. Its compact size makes it easy to carry around in a wallet or pocket, and it can be used for printing miniature images or graphics. Overall, while B10 paper may not be the most common size, it still has its uses in certain applications.