Unfortunately, the industry standard smallest size is usually a 28 - this is a case where you may have to work out your sister size for a 28 band. There are a few brands that do in fact make 26 sizes, but bear in mind that due to their exclusive nature, they may be more expensive than 28 sized alternatives!
Wait, there are sizes smaller than an A? Yes! An A cup indicates 1 inch of difference in band:bust, but a AA is less than an inch of difference, and a AAA is when there is no difference at all.
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