The most important item in your baby's swim gear is the Happy Nappy. Most baby swimming schools in the UK today recommend that all participating babies should wear such a nappy. After all, you want to go swimming with your baby and not with the contents of his leaking nappy. The swim nappies are made from 1mm thick supple, stretchy neoprene and are equipped with super soft, tight-fitting, deep fabric bands with high rubber content so they lock in all unpleasant sheddings. Developed by us - in mind of swimming instructors, parents and babies. So simple yet so effective - no cords, no Velcro fasteners, no elastics. IT WORKS!! Can be worn with or without ordinary swim nappies - an insert is recommended for easier cleaning. Tested and improved with the UK's leading swimming instructors. Sizes: XS - Newborn: 3-4 kg, waist circumference 32 cm, leg length 16 cm, S 0-4 months: 3-6 kg, waist circumference 34 cm, leg length 18 cm, M 3-8 months: 6-11 kg, waist circumference 36 cm, leg length 21 cm, L 6-12 months: 10-15 kg, waist circumference 38 cm, leg length 24 cm. XL XL XL 12-24 months: 13-18 kg, waist circumference 40 cm, leg length 26 cm, XXL toddler 24+ months: 16+ kg, waist circumference 42 cm, leg length 28 cm