I found one of these on the side of a trail in Yosemite. I picked it up to pack it out, but thought it was a pretty silly thing. Later, I discovered it fit snugly in the bottom of my ShopSack Medium and now it lives there, only emerging as a warm dry seat on camp outs, wet picnic tables, and cold cement benches.
Put it in the bottom of your ShopSack Medium or straight in your medium Wald basket to add extra padding for what ever you're hauling and cut back on rattle and noise.
It's made it the USA, inexpensive, and light, and there really isn't a good excuse why you shouldn't own one...
-Roman
Specs:
Colorways: Limon/Silver or Blue/Silver or Coyote/Gray
Flat Dimensions: 16 in x 13 in x 0.75 in (41 cm x 33 cm x 2 cm)
Folded Dimensions: 12 in x 2.5 in x 2.75 in (30 cm x 6 cm x 7 cm)
Mass: 2 ounces (56 grams)
Made in the USA
Therm-a-rest z-seat camping seat