The suit has a base of 2mm extremely flexiblenano-glide neoprene that provides great flexibility.1.5 mm around arms and shoulders for ultimatestretch. 4mm air cell panels on the chest and 6mmpanels on the upper thighs for maximum buoyancy,very important when swimming with your shoes on.Neoprene panels are placed to ensure free movementin the hip area while running. Front and back zipper toopen up easily while running. Two easily accessibleinner pockets for carrying extra equipment. Nylonpanels between the legs to reduce the frictionaldamage that could occur when running. Extra addednylon loops to easily fasten accessories. Comes with awhistle for security.