Polaris RZR XP 1000 X300 Heavy Duty AxleRhino X300 Axles Change the Game SuperATVs Rhino X300 axles for the Polaris RZR XP 1000 change the game. With a 300M shaft that flexes to absorb force instead of breaking, you get CVs that dont break, a drivetrain that wont buckle, and the ability to go on bigger, meaner rides. We take it over the top by backing it with a 3 year warranty the industrys best axle warranty. Its All About the Flex X300 is about more than brute strength, its about flex.