Pro Glides are easy to install, no tools or glue needed. The durable plastic upper frame snaps over existing swivel glides and lock into place. The Pro Glide protects your floors from scratches and rust stains. Pro Glides also help keep rooms quiet by reducing noise caused when students move the furniture around. With reinforced Gorilla Felt covering and a durable plastic frame that snaps over existing swivel glides, the Pro Glide will stand the test of time. Fits: 1 ⅛" to 1 ¼" diameter metal or nylon base chair glides.