Large Heavy Duty Office Chair Casters 3" (75mm) Softech Hardwood Floor Safe Wheels Set of 4 Thermoplastic elastomer rubber wheels - Safe for ALL floors Non-marking and non-marring - 3-3/16" Mounting Height Large size 3" (75mm) 165 pound capacity per caster High quality replacement for nylon casters Grip ring stem size: 7/16" diameter; 7/8" length