The spare glides were developed by Kartell fort he Dr. NO armchair. They are easily plugged in the chair-legs from above. Because of the different formed chair legs, Kartell offers special glides for the forelegs and the hind legs.
The spare glides save the chair as well as the floor on which it stands. Furthermore the intact glides reduce the noise that can be caused when the chair is moved. As the glides are available individually, the whole chair hasn't always to be retreated completely, but single glides can be bought specifically when they are needed.
The Dr. NO armchair is a classic from Kartell that became popular because of its perfect union of function and aesthetic. The star designer Philippe Stark designed it.