Office Chair Stationary Glides 5 pc Set replaces standard casters.  These chair glides are the same height and the stem is the same design as standard casters used on office chairs.  If you need your chair to stay stationary, then this the set of glides you need.  Metal stem length is 7/8", Stem diameter: 7/16" grip ring style, Base diameter: 2", Overall height: 2.25"