GreenSkin GS-4000CSI, is a state-of-the-art, 100% clean & green, super-sticky, crack isolation flooring underlayment. This cutting edge anti-fracture membrane just happens to tout TCNA"s highest performance crack strength level available on the market (ANSI 118). GreenSkin"s hi-tech approach, inverts the structure, as well as the traditional VOC/solvent based asphalt mind-set, by adding enormous strength and performance features to the membrane, while actually upgrading the glue strength/chemistry, to a PRIMERLESS, crystal clear, clean and green PSA / hot melt - eliminating toxins from the air you breath (i.e. asphalt based designs off-gas VOC/solvents). This design allows us to build in a moisture management ply of metallized polyester (METPET � looks like foil), add a clean & green anti-microbial agent to the topside nonwoven, and thus, provide you with a �beefed up,� water tight, non-wicking, high energy surface, with which to receive your desired thin set formulation. The best part of all of this, is that GreenSkin membrane is VERY price competitive ($/SF).