This stuff is Gore-Tex in a can! You can make any nylon garment waterproof and still breathable by spraying it with TX.Direct. You don’t need to spray the underarms (unless you need ultimate dryness), so breathability is enhanced. I’ve been using this stuff for years. I initially used it just on Gore-Tex (it really helps bring old Gore-Tex back to life). Then I gave it a shot on a nylon jacket and it worked just like Gore-Tex. Why spend hundreds on a waterproof jacket when you can spend much less, use this spray and get the jacket of your choice? (one can treats about 4 jackets). I also use TX.Direct on my boots that have nylon uppers, and spray my Woolrich felt hat, which works great — water just beads up on it; can’t even tell it’s there. The spray is somewhat smelly, so it’s best to spray it on outside or in the basement, and it does need to be re-applied after washing. Nikwax also makes a wash-in product you put in with your laundry. I don’t like excessively washing my technical gear, though, as it seems to wear out faster. I save the wash-in stuff only for when I do need to wash things, and freshen up my waterproofing when needed with the spray-on. I also don’t really like the idea of having those chemicals directly against my skin, so I prefer the spray-on generally because you’re only applying it to the exterior of the garment.