Public use

The public use bar under 35 U.S.C. §102(b) arises where the invention is in public use before the critical date and is ready for patenting. As explained by the Federal Circuit:


 * The proper test for the public use prong of the § 102 (b) statutory bar is whether the purported use: (1) was accessible to the public; or (2) was commercially exploited. Commercial exploitation is a clear indication of public use, but it likely requires more than, for example, a secret offer for sale. Thus, the test for the public use prong includes the consideration of evidence relevant to experimentation, as well as, inter alia, the nature of the activity that occurred in public; public access to the use; confidentiality obligations imposed on members of the public who observed the use; and commercial exploitation.. That evidence is relevant to discern whether the use was a public use that could raise a bar to patentability, but it is distinct from evidence relevant to the ready for patenting component of Pfaff 's two-part test, another necessary requirement of a public use bar.

Source
U.S. Patent & Trademark Office, Manual of Patent Examining Procedures 2133.03(a).