  We have developed a storage bottle for ultracold neutrons (UCN) in order to
measure the UCN density at the beamports of the Paul Scherrer Institute's (PSI)
UCN source. This paper describes the design, construction and commissioning of
the robust and mobile storage bottle with a volume comparable to typical
storage experiments 32 liter e.g. searching for an electric dipole moment of
the neutron.
