Simple, silicone, and stretchy! On the narrow side - check out the Screaming O Pro 3 rings if you want wider openings that are a bit thicker. 

This premium set of Cloud 9 Cock rings can improve stamina and prolong an erection. Made of 100% super stretchy silicone in three different sizes. Cloud 9 Cock rings can be used individually or together. Do not wear a cock ring for more than 30 minutes at a time.

Cloud 9 Novelties Silicone Stay Hard Ring Combo Pack includes a trio of super soft skin-safe rings that are made of phthalate free, non-toxic silicone. These rings are comfortable and made specifically for your safety and hygiene during intimate play.

Sizes: inner diameter 1.188 inches, 1.031 inches and 0.88 inch.