Featuring the warmth of Polartec® thermal fabrics, combined with a snug, 4-way stretch fit and a windproof membrane Polartec® Aqua Shell® fabrics come in two versions to accommodate above and below-water activities.
From the Polartec® LLC® website
"Designed for water sports of all types, these fabrics combine the maximum warmth of Polartec® fleece with body-hugging four way stretch. Its breathable windproof membrane and water-repellent surface provide excellent protection from the weather. Polartec® Aqua Shell® provides aerodynamic performance for skiing and cycling, and neutral buoyancy for warm-water diving."