Swimways Sea Squirts Killa Whale Swim Assist Vest Flexible back fin makes the vest fun to wear Smart buoyancy technology helps kids achieve proper swimming position Three floatation pads are easily removed by parents, helping kids gradually gain confidence in the water Quality neoprene, heavy duty zipper, and breathable fabric liner Small: 19-22" chest Medium: 22-24" chest Large: 24-26" chest