Callaway Golf filed a patent infringement suit against Acushnet over its Titleist Pro V1 golf ball. Callaway alleges that the Pro V1 uses technology covered by four key patents that Callaway acquired when it purchased Top-Flite Golf out of bankruptcy in 2003. The Pro V1 is reportedly the industry’s top-selling golf ball.

The suit says that the patents in question, which involve the use a solid core rather than the more traditional wound core, helped change the golf industry over the last decade. Acushnet has sold nearly a billion dollars worth of Pro V1 balls, which reportedly use the solid core technology covered by Callaway's patents.