Polyurethane Office Chair Caster Wheels for use on Hardwood Floor - Standard Stem Diameter: 7/16", Stem Length: 7/8" - 5 Units Pack - Grey Edge Soft Polyurethane wheels prevent scratch or damage to hardwood floor Maximum Weight Rating: 100lb/wheel Lithium based grease lubricated for smooth movement Stem diameter: 7/16"(11mm), stem length: 7/8"(22mm) fit most office chair models Contemporary grey color edge design