The revolution in trailer ball technology has begun with CURT Switch BallĀ® trailer balls. Gone are the days of needing to own separate ball mounts for your boat, popup camper and utility trailer. You can also forget the time-consuming process of unbolting a trailer ball and re-torqueing another. Switch BallsĀ® are an exclusive interchangeable trailer ball system that allows you to change trailer ball sizes with a simple twist.