If during a patent’s term anyone (without the patent owner’s permission) makes, uses, offers to sell, sells, or imports any patented invention within/into the United States, he/she infringes the patent. One who actively induces patent infringement is also liable as an infringer.
Whoever offers to sell, sells within the U.S., or imports into the U.S. a component of a patented machine, manufacture, combination, or composition, or a material/apparatus for use in practicing a patented process, which constitutes an invention’s material part, and who knows the same to be especially made or adapted for use in a patent infringement is liable as a contributory infringer. However there is no such liability if the item in question is not a staple article or commodity of commerce suitable for substantial non-infringing use, such as an interchangeable product, e.g., a keyboard usable with multiple computer brands.