Lightweight ribbed swim fabric Elastic waist Functioning drawstring Contrasting drawstring and waistband Partially-lined inside Outer: 90% nylon 10% spandex Lining: 95% terylene 5% spandex Sizing: True to size. For sizes 0-6M and 6-12M, size up one size if in between sizes. For example, if child is 3 months, we recommend buying 6-12M. For sizes 12-18M through 4-5T, buy child's current size. Size up if at the end of size range. For sizes 5-6T and 6-7, we recommend current size or size down one if child is skinny or for a more fitted look. You can size up when in doubt, but we do not recommend sizing up several sizes above your child's current size. Keep in mind swim fabric has stretch but also becomes looser when in the water. The best way to find correct sizing is to choose a similar item (preferably swim) that fits your child well and measure laid flat.