Glides for 1951 chairs and stools are offered in three versions, for different types of use. All glides ship in a set of four and fit all 1951 chairs and stools. Standard glides: hard polycarbonate plastic, for all-around use, including outdoor. Hard floor glides: with felt inserts, for indoor use only. Noice reduction glides: partial noise reduction, for all-around use, including outdoor.