This long sleeve crew neck and pants set retains the body warmth but using a special fiber from 32 degrees. The quick dry feature keep the children dry and comfortable, which helps regulate the body temperature. the stretch yarns maximizes the comfort providing durability and lasting shape. Special agents reduces clinging and minimizes unpleasant odor caused by perspiration Sizing: X-small (4/5, 32-41lbs), Small (6/7, 42-59lbs); Medium (8/10, 60-72lbs); Large (12/14, 73-99lbs), X-Large