The Speedo Learn to Swim Jammer is built with Spandex Xtra Life fiber which is engineered to have 5-10 times more durability than ordinary spandex fabrics.Suit provides resistance to suntan lotions, skin oils and chlorine better than conventional fabrics. This fabric helps resist sagging and bagging, keeping swimwear fitting newer longer. Speedo's exclusive UV Block the Burn with UPF 50+ protective fabric features more body coverage for greater sun protection a tighter knit fabric provides for higher level of protection from the sun's harmful rays. Improved fit so over-stretched product does not decrease the UPF rating. The Learn to Swim Jammer has an internal draw cord for a great fit. The fabric is made from 80% nylon and 20% Spandex Xtra Life fiber.