DUI makes insulation utilizing 4 different materials: Thinsulate B (Ultra); Thinsulate Liteloft; Polartec PowerStretch and one-way stretch fleece. Each material has its pros and cons, and the key to your selection is to determine which material offers maximum effectiveness for your diving. Thinsulate Type B (the type that is used in footwear and is already compressed) is excellent for those who want their insulation to retain insulating value even if it gets wet. Many technical divers or others who may not be able to leave the water if they get wet prefer Thinsulate for these reasons. Thinsulate B (Ultra) comes in two thicknesses: 200g and 400g and provides the greatest amount of warmth per unit of thickness of any insulation available. Thinsulate Liteloft will be warmer on the surface as its high loft is excellent for cold surface conditions. That high loft means that underwater the compression will decrease its insulative effectiveness to that of somewhere between the 200 and 400g Th