Enhance your erection and pleasure your lover with TPR stimulator cock rings. You'll stay hard longer and provide additional sensation during sexual intercourse. Three purple rings - in various sizes - included for a hard on that lasts all night long. Do your penis a favor and slip one of these on the next time you have sex. Diameter: 0.75”/2 cm (small), 0.85”/2 cm (medium), 0.9”/2 cm (large)