Find 28AA bras for a petite frame and a smaller bust, where a snug band and the right cup shape make all the difference. At this size, the band should sit firm and level without riding up, the cups should lie smooth with no gaping at the top edge, and the straps only need to steady things, not hold them up. If you are unsure whether 28AA is the right starting point, use our Bra Size Chart before choosing your next style.