Occasional Shakedry user here, that stuff is truly amazing. But, just as advertized, only in a very narrow usage profile, e.g. strict no backpacks rule (unless

Occasional Shakedry user here, that stuff is truly amazing. But, just as advertized, only in a very narrow usage profile, e.g. strict no backpacks rule (unless the bag fits inside). All the magic comes from the single trick of exposing the bare, delicate membrane as the outer layer. Usually there is a protective outer layer on top of the membrane that will inevitable get soaked and then it's game over for breathability, no matter how good the membrane underneath is. A backpack would ruin that unprotected membrane in no time and I don't even expect it to last very long even if just occasionally taken along for uncertain weather.