Its probably a fake... thermal dynamics are pretty ridgid and you can't just make believe new rules.
Unless its a huge sponge that continuously drips on you and if you leave it in water for 120 minutes and it is like 14 feet thick...but I seriously doubt that water will last 5 days.
Evaporating water is basically called swamp cooling..and that doesnt look to be all that effective of an surface area...especially if its under your jacket. The basic fundamentals of a swamp cooler is that you need lots of wet surface area to blow warm wind across...to make cool air out the other side. But that water evaporates and then no more cooling... I doubt 2 hours of water soaking in that thin of a membrane will even last 1 day of track riding, let alone 5. And I dont see air passing thru it and not water....
I am sure its just another materal like: Hyvent. XCR. Polartec. Gortex. eVent. H2No Barrier. DriClime. Coolmax
I am also willing to bet this will be hotter than just wearing cotton under your jacket