The Convex: Beautifully contoured, the Convex erection ring provides style and comfort in a phthalate-free Super Elastique 3000 elastomer. Super Elastique 3000 stretch-to-fit is very durable, provides a great fit, and helps maintain extra hard erections. These cock rings combine quality and comfort for your best performance. This erection ring comes in colors black and clear. The Convex cock ring: • contoured shape provides style and comfort • compatible with silicone personal lubricants • easy to clean with soap and water