While I wouldn’t want these to be my initial cup for camping or any survival situation, they are excellent back up solutions that you can make on the fly. They fold down flat and can stack into each other when made in different sizes. These duct tape cups are as durable as any other drinking utensil and in some ways more so, its duct tape for crying out loud!
As long as you use a hefty duck tape they do not give off any taste or odor, just make sure to use cold drinks only, as hot liquids may break down the tape and possibly tarnish the water. These are easy to make, light weight and are almost free. They take up no space and the concept alone for those reasons is quite interesting.
In a pinch most people have access to duct tape, so learn how to put together a makeshift cup and you will never be with out one in time of need!