In 100 or less: compact camp coffee.
The X-mug is a collapsible 2 cup mug which does exactly what that implies. Inside are measurement graduations in fractional cups and milliliter.
The X-Brew is the X-Mug made into a pour over coffee system with a base that can stand atop various containers, including the X-Mug.
It includes a removable stainless dual mess (fine one one side for grounds filtration, coarse on the other for strength) for your choice of using a paper filter. Works well atop multiple containers. I’ve used it on a Kleen Kanteen vacuum bottle and a Bodum travel mug.