Curtain Ring: The outer diameter is approximately 37 mm/1.45 inches and the inner diameter is 30 mm/1.18 inches. For curtain rods with a diameter of less than 27 mm/1.1 inches, please ensure the size is correct when purchasing. Quantity: 40 black metal curtain rings per pack, enough for daily use and replacement. Installation: Thread the curtain ring one by one onto the curtain rod, then thread the curtain hooks through the small ring. You can then easily slide the curtain. Good Design: The curtain rings are well-polished with a burr-free surface. These curtain rings are made of durable black metal and built to last. Wide Application: These curtain rings are widely used for most types of curtains, such as shower curtains, window curtains, French window curtains, etc. Please check the size before purchasing. Pack of 40 metal rings for hanging curtains and rods, 30mm inner diameter. Sturdy Curtain Ring: Made entirely of robust metal with a strict design, the rings run smoothly and do not deform or fall off suddenly. Durable and Rust-Resistant: The black metal curtain ring is made of durable metal with a non-porous surface, ensuring it lasts for years without rusting. Eliminates Scratches: The beautifully polished and smooth surface is free of burrs, allowing you to hang your curtains without them snagging, pulling, or tearing. Wide Application: These black curtain rings are widely used for most types of curtains, such as shower curtains, window curtains, patio door curtains, etc. Please check the size: The inner diameter is 30 mm / 1.18 inches. For curtain rods with a diameter of less than 27 mm / 1.1 inches, please ensure the size is correct before purchasing. Specifications: Size: Outer diameter: 3.7 cm / 1.45 inches; Inner diameter: 3.0 cm / 1.18 inches; Material: Metal; Color: Black; Quantity: 40 pieces; Package contents: 40 x Curtain Rings