Penn is one of the most recognized names in tennis balls. Penn was started in Jeanette, Pennsylvania in 1910. Since then they have developed some of the most important tennis ball enhancements. Penn was the first to invent pressurized ball cans. Next they invented the first fluorescent yellow tennis balls. In 1973, the USPTA used Pro Penn tennis balls as their official ball. Throughout the past 100 years Penn has made revolutionary discoveries that have continually improved the tennis ball.