Function

• Patent marking informs the public that the item is duly patented. According to the United States Patent and Trademark Office (USPTO), "penalty for failure to mark is that the patentee may not recover damages from an infringer." Without correct marking, it may be difficult to prove deliberate infringement.
  
  

Patent Mark

• According to the USPTO, to properly mark an item, "the patentee is required to mark the articles with the word "Patent" and the number of the patent." Utility patents are marked with seven- or eight-digit numbers. Plant patent numbers are marked with a sequence of five or six numerals preceded by "PP." Design patent numbers are six or seven numerals following the letter "D."
  
  

Pending

• The terms "Patent Pending" or "Patent Applied For" have no legal power but serve to inform the public that an application for patent protection has been filed or pursued. No protection exists until the patent is applied for and granted.
  
  

False Marking

• It is illegal to incorrectly mark an item as patent protected. Violators may be subject to fines of "not more than $500 for every such offense," according to the USPTO.