Compatibility: Gym replacement wheel fits for all fitness room models 2000, 3000, 3000 XL and some early XL. The diameter of the bearing is about 6MM, please check if it meets your needs before buying（Please note that these will not fit if the wheels of your Total Gym have bearings sticking out on one side.） Strong and durable：Wheels are made of high quality engineering plastic, round wheel design structure. Better withstand the pressure, not easy to damage. The bearings are made of high pressure forged steel, the whole is more smooth. Quieter when working. Give you a better application experience. Advanced Design: Gym replacement wheel's overall design adopts a newly upgraded circular wheel structure, which is stronger to resist, and it is not easy to damage Package Included：Package includes four replacement wheels High Quality Bearings: 626ZZ bearings are made of high quality stainless steel. Compared with 626RS bearings, they have better stability and ultimate speed, low noise and smooth rotation.