Lucite Acrylic Curtain Rings with Eyelet are 1/4" thick solid Lucite rings, not hollow. They are 100% Lucite. The price is per ring. Inner diameter: 2" Outer diameter: 2 1/2". Elegant and unique curtain accessories, this Lucite Curtain Rings Set adds a modern touch to any window. Wipe clean with a dry cloth.