Sea to Summit's X Set 11 comes with two collapsible X Mugs and the collapsible X Pot/Kettle for making freeze-dried backpacking food. These three items collapse and pack inside each other for compact storage, and their flexible silicone walls enhance lightness and handle boiling water safely. The X Pot/Kettle has an aluminum base to work with backpacking stoves, and the glass-reinforced handles help pour boiling water into freeze-dried packages.