These round replacement disc cap chair glides for wrought iron patio chairs and tables install over a flat round metal disk on the bottom of the furniture leg with an outside diameter of 1-7/16". The inside part of the glide is 3/16" deep. Your disk should not be any thicker. The overall height is 9/32".
These nylon chair feet will protect your patio surface from scratches. They will also lower the noise when moving your outdoor furniture.