Each Rodger system comes with one pair of underwear. Additional briefs are useful when your child wets multiple time a night, or you don't do daily laundry. Rodger brief sizes above are roughly equivalent to the Hanes size indicated. We strongly recommend measuring your child's waist to accurately size him or her. Shrinkage will occur. When you receive the briefs, try them on first to make sure they fit. Used/washed briefs are not returnable. If you have any questions, please do not hesitate to call our customer service specialist at 1-800-998-1745.