Some items are adjustable or elastic enough that they come in combined sizes. For example, an item might say it's available in two sizes, S/M and M/L, or it might say 1X/2X and 3X/4X. This means, for example, that a size S/M will fit you if you are either a S or M as shown in the lingerie size chart. Likewise, a size M/L will fit you if you wear a M or L, as shown in the lingerie size chart.
