New and unused set of four (4) machined wheels/rollers compatible with Total Gym Replacement. The diameter of the bearing hole is approximately 5/16 inch. All bearings are included. Fits 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 solid engineering plastic material. This means your gym will be up and running quickly and operating at maximum efficiency. The wheels are designed with a smoother and quieter material. Lab and gym tested and approved. STRONGER, QUIETER, and LASTS LONGER than original and all other aftermarket products!!! Manufactured and tested to perform as well as original OEM parts but at a better value than a comparable original equipment manufacturer part. Please feel confident in purchasing.