Keller - POLARIS RZR RS1 Mega BALL JOINTA Bigger, Better Ball Joint When you ride your Polaris RZR RS1, you have to be able to go big without breaking down. After all, you dont have a co pilot to help you out of sticky situations. So get Kellers Mega Ball Joints for the most durable ball joint on the planet. They use oversized components to give you all the strength youll ever need. And when you combine that with their two piece design, youll hit your machines limits long before you break