The thermal body, made from 0.5mm neoprene, provides the warmth of a 2-3mm wetsuit, largely due to its hi-tech four layer construction and lining. The sleeves and collar are made from chlorine resistant polyester to provide extra mobility and comfort. Both the sleeve and body materials carry a UPF 50+ rating and are highly durable in the chlorine and at the beach. Heatseeker one pieces are made with a back zip to provide optimum comfort and fit.