Transitional Phrase - Hybrid Transition

Hybrid Transition

A third kind of transition, the hybrid transition, uses the phrase "consisting essentially of". The effect of this transitional phrase is to leave the claim "open" to include additional elements, but only if those additional elements do not materially affect the basic and novel characteristics of the claimed combination. In this instance, the pencil with the eraser added might still not be infringing, but a pencil with a fin or a non-functional button would still infringe, because the thing that was added would serve no purpose material to the claimed functions of the pencil. This language assists in avoiding prior art, but is broad enough to capture imperfect attempts to copy the patented device.