A road consisting of concrete, grass and stone leads to a two-storey box, a skeleton structure made of glued spruce wood with a façade of rear-ventilated, blue-painted wood-cement panels. The ground floor accommodates the customs office, the preparatory kitchen for the paddle steamer on Lake Constance, public toilets and the ticket office, while the first floor houses the Lake Gendarmerie. The waiting area for the passengers of the paddle steamer "Hohentwiel" is protected by a corrugated iron roof resting on slender round steel pylons. Its broad side corresponds to the narrow side of the "Blue Box", but being higher and in particular longer than the latter, it definitely reigns over this building.