5.25 oz. The blue fabric is Momentum that I had left over from a bivy project. The beak did not reach all the way to the ground without it, but the extension could be left off and it worked fine in the woods without them. Thought I might be more exposed on the JMT this summer, so I added them. I also used shock cord and toggles for adjustable tie-outs. There are lighter alternatives.
The tarp and beak with all the ties, 12 stakes in the silnylon stuff sack weighs 19 oz.
Therefore,the SpinnTwinn alone with 12 stake sand lines would be around 14 oz.
A great shelter less than a pound for one person. Its a tight shelter for two.