T.D.S.™, or Thermal Defense System, is Volcom’s advanced temperature control structure, found throughout their line of jackets, pants, and layering. This system strategically places extra insulation in key areas where warmth is most crucial. On example is that additional insulation is often placed in the body of jackets to keep your core temperature up. While T.D.S.™ adds extra insulation in some places, it also eliminates excess insulation in the areas of the garment where the most sweat and heat are generated. This, coupled with ventilation, gives you ultimate weather protection while keeping you dry from the inside out.