Size Guide - Base Rings
X-Lock base rings come in eight sizes, from inner diameter 1 1/2" (~38mm) to 2 3/8" (~60mm):
Size 0 is very small. If you're considering Size 0, we recommend trying Size 1 first unless you're really sure.
Sizes 6 and 7 are very large. If you're considering them, we recommend trying Size 5 first.
Three ring styles
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.
We recommend starting with the standard ring, unless you're experienced with other devices and already know you need a different type.