In an effort to combat potential counterfeiting, more than 100 footballs used in Super Bowl XXXVI were marked with a synthetic DNA (deoxyribonucleic acid) strand by Professional Sports Authenticator (PSA) of Newport Beach, California. PSA Product Manager Steve Ryan explains, "There is a specific chain-of-custody with the footballs. Prior to the game, we apply the invisible DNA-laced ink to each ball. NFL Officials then take them to a secure location where they are issued throughout the game. As each ball leaves the field, we verify its authenticity using a specially calibrated laser." Although invisible to the naked eye, the DNA mark becomes fluorescent green when illuminated with the proper laser frequency. In using this method, authenticity can be determined many years from now even when the footballs have changed hands.