Swim-sters special needs swim diapers are perfect for anyone who requires a diaper while swimming. They are designed to be worn discreetly under a swimsuit so they are perfect for individuals with bowel incontinence. Swimsters effectively contain solids. Sizing: XS-Size 6/8-Waist:17"-24", Weight: 40-58 lbs; S-Size 8/10-Waist:18"-27", Weight: 59-74 lbs; M-Size 10/12-Waist: 20"-29", Weight: 75-89 lbs; L-Size 14/16-Waist: 21"-32", Weight: 90-118 lbs; XL-Size 18/20-Waist: 22"-34", Weight: 119-141 lbs.