It is Nylon Tafta (210T). Silnylon it's not. I've had mine in a steady overnight rain and it did not leak. At 13' it provides plenty of coverage. I've considered his new 10x13 rectangular tarp as I thought it would be good to sit under. Keep in mind I'm not a big long distance hiker at this point so weight is no biggy for me. I could be carrying two Jungle Hammocks and it would still be lighter than what I used to use as a ground dweller.