REI Minimalist Bivy
Very good condition, probably has less than a dozen nights out. Waterproof/breathable almost all over, except the mesh part by your face.
In practice this works great, a rain jacket, small tarp, umbrella, helpful tree, etc is all you need to keep rain off your face while the rest of you is dry and it’s easy to breathe.
No delamination of seam tape nor of the gore-tex type membrane.
This review covers it pretty well. BicycleHobo.com — REI Minimalist Bivy Sack Review
$50 + ship
Something like a Nalgene or big 26oz bike bottle. I had a very small stuff sack I used to put it in then shove in a bottle cage, of course it was taller than the cage and kind of squished in there but maybe that gives an idea?
I’m interested I want something to carry on summit days or Car to Car shit where I need emergency kit but am making myself not buy gear while my back is hurt.