Abstract: A device for storing liquid comprises a housing having side walls, an inner cavity wherein said housing comprises two unequal vertical parts and is designed to prevent said liquid being spilled and to revert to the vertical position when the vertical symmetry axis of said device leaves the original. The center of mass of said device filled with said liquid is at the bottom of said housing, lower than the geometrical center of said device. The lower outer surface of said housing is convex and is a sphere segment. The upper part of said walls of said housing is bent towards said inner cavity to form a central aperture for filling and emptying said inner cavity such that said liquid stored in said inner cavity cannot be spilled when said device leaves the vertical.