Stored in the gamepocket of my Filson packercoat, itself a major shelter is a Campmor 9'x9' ( finished)coated nylon tarp with preknotted tiedowns. It isn't the lightest compared to the premium siltarps, certainly more expensive than the affairs you use for painting. Size was determined simply by that week's paycheck. I got the biggest my budget would allow. Shelter follows the same dictate of all homes- location,location,location. The tarp is merely the foundation for my shelter options using additional materials. I've practised several of the configurations on our homepage article. My favourite replicates the origami 'Rock.' If I can't throw a basic shelter up in a few minutes I'll just wrap myself up in the thing.