Xcup

They look like a cross between something from Inspector Gadget and Dr Seuss, but if you don’t mind that (and who would) you’ll love the X series from Sea to Summit, including this cup. Made of flexible silicon sides that are freestanding and rigid and yet collapse completely flat, they are nifty and generously-sized. Because of their collapsibility, they can afford to be high-volume when set up, meaning you can finally have reasonably-sized receptacles on your most remote trek. The  X-Cup flattens down to 15 mm, is BPA free and highly heat resistant.