The cock rings gradually widen into diameters of 1.875, 2, and, 2.25 inches. The "Ulta-Premium SiliconeSilk" creates a slightly softer feel when touched against skin. When used with some water-based lube these rings can be positioned with great ease. We never had a problem with them shifting around unnecessarily either.
The box mentions using all three for the ultimate control but we felt that using two was just fine for our desires. All three are solid silicone and can be cleaned as such. There are instructions on the box if needed. All in all, these rings do exactly what you would expect them to. And, you can get down with your bad self in either violet or magenta. It's all about the options.