zitriom Premium Office Chair Caster Wheel Universal Standard Size 11mm Stem Diameter X 22mm Stem Length (7/16" X 7/8") Pack of 5 RELIABLE - These Premium Casters are especially designed to Protect Carpet, Slate, Tile, and other Soft Floors HEAVY DUTY - Office Chair Caster Wheels Maximum Weight Rating: 100 lbs EACH wheel and 500 lbs as a set of 5 PRACTICAL AND DURABLE - Made of high quality polyurethane to guarantee excellent performance over time UNIVERSAL - These rollers fit most office chair models available - Standard stem diameter: 7/16"(11mm), stem length: 7/8"(22mm) USER FRIENDLY - DIY Easy pull and snap installation - 5-year Warranty - Free No-hassle replacement or money back guarantee