Blush Novelties Performance Silicone Cock Rings. Performance Cock rings constrict the blood flow in the penis, which helps to maintain your erection and increases stamina. They can also heighten sensitivity and make orgasms more intense! Since it's silicone it can be completely sanitized. Performance Rings are very comfortable and stretchy. It can be stretched up to twice its original diameter. 3 pack. For you and your partner. Specifications: stretchy and strong. Non-porous. Hypoallergenic. Phthalate free, non-toxic materials made using pure silicone. Pack of 3 same size rings 1.75 inches in diameter.