Use the Pathfinder Bottle Stove to expand your Pathfinder Bottle and Nesting Cup, 0.9 litres. With this base you can heat up all your food in the Nesting Cup. To use the stove you first need to build a fire. By placing the base over the fire it will be ready for use. If you want to keep the fire alive in the mean time you can add sticks to the fire via the opening in the front.
The Cup was designed as such to make sure the Bottle fits perfectly inside.