- A comfortable stitch construction that doesn't irritate your skin and super strong and durable. FTM:56% NYLON/33% POLYESTER 11% SPANDEX FMJ: 90% POLYESTER/10% SPANDEX Wetsuit Partial meltdown thermo lining makes sure that you stay warm. The atomic flex- still offers exceptional freedom of movement and warmth and is the runner op for nuclear flex. These rolled seals are tight to keep cold water out and warm water in.