Inner diameter: 2.25" Outer diameter: 3" Our small rings are best used with light weight and/or very smooth fabrics. They are well-suited to closed tail slings. If you plan to make your sling very narrow (22"-26"), you might also want the small rings. The small rings tend to be very secure, though not as easy to adjust as the larger rings. They are also good for onbuhimos, and waist bands where one would otherwise use a buckle.