Glides for 20-06 chairs and stools are offered in three versions, for different types of use. All glides ship in a set of four and fit all 20-06 chairs and stools. Standard glides: TPU plastic is a softer plastic, for allround use, including outdoor. Hard floor glides: with felt inserts, for indoor use only. Carpet glides: hard polycarbonate plastic, designed to reduce friction. Also approved for outdoor use.