New and Never Used Set of four (4) Machined Wheels/Rollers Compatible with Total Gym Replacement. The diameter of the bearing thru hole is about 5/16 inch. All bearings are included. Fits for Models 1000, 1100, 1400, 1500, 1600, 1700, 1800, 1900, Achiever, Core, Elite, Force, Gold, Gold Plus, Max, Platinum, Platinum Plus, Power Platinum, Premiere, Pro, Supra, Supreme, Ultima, Ultra, X-Force, and XLi. Our rollers are made from high quality material solid engineering plastic. That means your Gym is going to be back up and running quickly and operating at peak efficiency. Wheels are designed with smoother and quieter material. Lab and gym tested and approved. STRONGER, QUIETER, and LAST LONGER than originals and any other aftermarket products!!! Manufactured and tested to function as well as original OEM ed Parts but at a better value than the a comperable original equipment manufactuer part. Please rest assured to buy.