In forensic science, physical evidence can be categorized into having class or individual characteristics or both depending on the type of evidence. Class evidence is material in a criminal investigation that can be linked with a group of people, but not a specific individual. Class characteristics are measurable features of a specimen that indicate a restricted group source, but not traceable to an individual person or item. Examples of class evidence include blood typing, tire marks, and footprints. Class evidence can be used to narrow down a list of potential suspects by excluding people who do not meet the parameters set by the evidence. However, class evidence is not absolute proof that a suspect is connected with a particular location, and each bit of class evidence taken separately may not be strong. In contrast, individual evidence can be associated with a common source with a high degree of certainty, such as fingerprints, DNA, and striations on a bullet. Individual evidence is stronger in court, but class evidence can still be useful.