4 American Star 4130 Chromoly Ball Joints For Polaris RZR 900 50, 55, 60 Inch. 2015 up Very Easy To Install and Replace Durable , Tough and Long Lasting Zinc Plated Finish Replaces Polaris part numbers 7081924 Approximately 3 Times Stronger Than OEM Ball Joints Manufactured Out Of Super Strong Aircraft Grade 4130 Chromoly