MATERIAL - Decorative, high quality metal with permanent coating for long lasting rust protection. Stronger clips support heavier applications. DIMENSIONS - These metal curtain rings have an inside diameter of 38mm and will fit curtain rods up to 33mm. Please pay attention to the correct size when purchasing. EXQUISITE WORKMANSHIP - The black curtain set has no pinpoints or digging holes, won't scratch your fingers and the curtains can move smoothly and quietly. EASY INSTALLATION - The metal curtain can be easily pushed into the curtain rod, and the plastic curtain hook is attached to the ring, no additional tools required is not required for use Wide range of uses - metal curtain rod rings, suitable for a variety of curtains of different colors, suitable for hotels, restaurants, bars, meeting rooms , bedrooms, bathrooms, etc.