Zoggs deep sea bobin zoggs deep sea bobin jacket offers complete freedom of movement in the water encouraging children to develop a natural swimming position puncture proof floats are removable allowing you to adjust buoyancy as your childs confidence grows and therefore use the bobin jacket for longer whilst your child steadily learns how to swim outer 100 neoprene inner 80 nylon 20 elastane age 2 3 years 15 18kg and age 4 5 years 18 25kg adjustable buoyancy