Four (4) mechanical wheel/roller games can completely replace the gym. The through hole diameter of the bearing is about 5/16 inch. All bearings are included. Support models 1000, 1100, 1400, 1500, 1600, 1700, 1800, 1900, Achiver, Core, Elite, Force, Gold, Gold Plus, Max, Platinum, Platinum Plus, Power Platinum, Premiere, Pro, Supra, Supreme. Our rollers are made of high-quality engineering material solid plastic. This means that your gym will run again, and it will run at the highest efficiency. The wheels are made of softer and quieter materials. Tested and approved in laboratories and gyms. Stronger, quieter and more durable than the original and any other after-sales products. ! Manufacturing and testing functions and original OEM brand parts, but with better value than original compatible equipment manufacturer parts. You can buy with confidence. Qty.4 Machined Wheels/Rollers Compatible Total Gym Replacement, Fits Models 1000,1100,1400,1500,1600,1700,1800,1900,Achiever,Force,Gold,Max,Platinum,Platinum Plus,Pro,Supra,Supreme,Ultima,Ultra,XLI