As a general rule, use on non-public property, for example in factories and barracks, is not considered as use made available to the public, because company employees and soldiers are usually bound to secrecy, save in cases where the objects or processes used are exhibited, explained or shown to the public in such places, or where specialists not bound to secrecy are able to recognise their essential features from the outside. Clearly the above-mentioned "non-public property" does not refer to the premises of a third party to whom the object in question was unconditionally sold or the place where the public could see the object in question or ascertain features of it (see the examples in G‑IV, 7.2.1 above).