Caster Classics 5-Pack 2-inch Antique Brass Ball Chair Caster For METAL or PLASTIC Office Chair Style Chair Base Only. Pops into base. NO Socket. 2" Ball Roller - ADDS 2-5/8" Height to Chair 7/16" x 7/8" (11mm x 22mm) Grip Ring Stem - Replaces 7/16" Diameter Stem ONLY For Low Pile Carpet or other Non-sensitive Flooring NOT for use on Hardwood or Laminate