Standard Rings: 8mm thick. These work for most people.
XD Rings: Extend forward by an extra 2.5mm. This tightens the gap, and also makes the rings more rigid. Good for people with smaller balls to prevent escape.
Curved Rings: 5mm backward curve at the bottom. The extra space makes them feel about a half-size larger. Good for comfort. Ideal for people with large, high-and-tight balls. People with smaller balls can be more likely to slip through the gap.
Unsure about size? Click here to review our size guide.