These swim diapers are designed to contain solids, do not absorb or contain liquids, do not add weight, are made specially to fit under swimwear comfortably, and are reusable. Made by Pool Pals these swim diapers are specially suited for the needs of infants and young children who require a diaper while swimming. Sized by weight. Sizes: Baby (10 to 20 lbs), 2T (20 to 30 lbs) 3T (30 to 40 lbs) & 4T (40+).