Curtain Ring Size: 45mm inner diameter, fits diameter 28mm curtain pole. 12PCS curtain rings in the box. Noise-Free: We insert nylon to ensure a smooth and quiet glide when opening and closing your curtains, as well as to prevent scratches to the curtain pole. Durable Construction: Crafted from high-quality metal, our curtain rings ensure long-lasting use without rust or corrosion. Smooth Glide Advice: Maximize curtain smoothness by maintaining ample space between the curtain pole and rings. Attention: Ensure the inner diameter fits your curtain pole prior to purchase.