These swim diaper sets for girls are worn as a bathing suit and are a perfect match to the My Pool Pal flotation swimwear and hats. My Pool Pal Reusable Swim diapers are proven to significantly reduce the risk of deadly E. coli bacteria being released into water by infants and toddlers who wear them, based on a University of Georgia report. The reusable products are up to 98 percent effective.Sizes 12 months to 4T...12 months:10-15 pounds, 18 months: 15-20 pounds, 2T: 20 to 30 pounds; 3T: 30 to 40 pounds; 4T: over 40 pounds.