For a tent or tarp?

Its 3/4 ounce per square yard, $12.50 per yard

They say it's too loud for a tent but I wonder about this

It has a DWR coating, not silicone, so I wonder how much it leaks rain

Silicone coated spinnaker cloth isn't available

Jerry,
Don't waste your money. It will leak plenty.
As for noise, most of the spins are about as stiff and noisy as you can get. IMO, cuben is only about half as noisy. I think SF will send you samples for around $2.
Please check to see they are at least a foot square, and test before you buy. I use 9" embroidery hoops over bait buckets, and wait for a big rain or two, or three. I have learned much more from this approach than I ever did using a hose. Of course, we get plenty of rainstorms here.
It is frustrating that there are no very light weight polyesters available to DIYers on the market that are supple and water resistant enough for a tent. I am experimenting with Epic Malibu treated with Aksto silicone spray and getting very good results. And no noise for sure. OWF has recently had Malibu, but it is very dark. too much so for a tent I could live in.
Some of the tent manufacturers use very light coated polyesters, so they are out there.
If you can't wait, try cuben. No sag, only moderately noisy, and much lighter than anything else.
Sam