The Must Vibra Ring Phosphorescent glows in the dark! It has been developed to transmit maximum sensations during sexual intercourse. This erection ring, made of high-quality silicone, helps delay ejaculation and maintain erectile dysfunction for longer durations. The Must Vibra Ring is certainly one of the best vibrating rings in the world. Designed by Clara Morgane, it has undergone extensive research for maximum stimulation for both partners. Its great flexibility makes it suitable for any penis size. The ring features a small switch to turn it on and off at any time. It can be used with or without protection. Batteries are included with the ring.