Old Navy Reversible Cut-Out Back One-Piece Swimsuit To reiterate again, adjustable is key, especially for anyone with a large cup size and a smaller band size, and this Old Navy Reversible Cut-Out Back One-Piece Swimsuit ($25-$35) has nice, thick straps and a tie to tighten, too. Image Source: oldnavy.gap.com Old Navy Reversible Cut-Out Back One-Piece Swimsuit $25 from oldnavy.gap.com Buy Now