Originally Posted By: Omega
I was thinking about some suitable shelter that is compact and can be easily carried for emergencies, particularly in cold windy conditions. ... but smaller and lighter, can be achieved by an emergency shelter, ...not going to be a comfortable or long-term resting equipment, but good enough to survive.

.. another extreme - heat. In this case, you need a sun protection ... relatively lightweight. ...


Space blanket. The cheap ones, though, are effectively single use.

Can't fold them back up but are useful to break the wind in cold (but doesn't insulate) and also protects from sun in heat.