Bivvy sack

[Shawn]

Anyone ever heard of a bivvy sack?

It's like a sleeping tarp and a tent combined.

Here's a quick example:

https://www.rei.com/product/203558/outdoor-research-helium-bivy?CAWELAID=120217890017583469&cm_mmc=PLA_Google%7C21700000001700551_2035580004%7C1190538631613%7Cbrand_flag%7C12511984293&gclid=2a8222834f701d119ec14a559ed17f56&gclsrc=3p.ds&msclkid=2a8222834f701d119ec14a559ed17f56

It's basically an alternative to a tent. It looks lighter and easier to pack. Might be ideal for ultralight hiking.

Anyone have any experience with these?