3 inch Swivel Plate Caster Wheels, Set Of 4 by Knights Of Armur SMOOTH.. gliding wheels with precision ball bearing swivel plate! Rolls great whether on carpet, hardwood, concrete or tile floors. 4 wheels included in set! Load capacity approx 150lbs each! Wheels are 3 inches in circumference and plates on each wheel measures 3 X 2.5 inches!