a whole and for the brand, which had traditionally used a wound-ball construction (with a liquid-filled core center) for its top-of-the-line golf balls. Shortly after its introduction the Titleist Pro V1 became the most played ball on the PGA Tour and has been for the past 20 years, picking up the most worldwide wins from both direct brand ambassadors (meaning they play Titleist equipment) and players who are not directly under contract and considered brand ambassadors from Titleist. Three years after Titleist's initial breakthrough with the Pro V1 came the Pro V1x, a ball with 60 fewer dimples. The combination of a larger firmer core, a thinner cover, and 60 fewer dimples resulted in a ball that retained the same soft feel of the Pro V1 while reducing spin and increasing distance. In December 2007, Acushnet lost a patent infringement suit brought by Callaway. The following November, Callaway won an injunction in a Delaware court, ruling that sales of the Pro V1 golf balls must be stopped from January 1, 2009, with professionals being able to continue with their use until the end of the year. Acushnet immediately announced that they would be appealing the decision. Acushnet somewhat redesigned the Pro-V1 during the dispute. On August 14, 2009, the Court of Appeals for the Federal Circuit vacated the judgment against Acushnet and ordered a new trial. On March 29, 2010, a federal jury ruled in favor of Acushnet (Titleist), and found that the Callaway patents were invalid. Endorsements Titleist has maintained endorsement deals with many leading professional players, including Danielle Kang, Jessica Korda, Adam Scott, Cameron Smith, Jordan Spieth, Steve Stricker, Justin Thomas and Will Zalatoris. Players previously contracted with Titleist include Tiger Woods and Rory McIlroy, before both moved to Nike, and Phil Mickelson, who switched to Callaway shortly after his 2004 Masters Tournament win. References External links Sportswear brands Golf equipment manufacturers Sporting goods manufacturers of the United States Products introduced in 1935