This double vibration penis ring not only lock penis and scrotum. but can stimulate your testicle. slow blood flow. make you harder. stronger and last longer. 10 powerful vibration modes. you can adjust the speed to exercise and trains sensitivity to increase endurance. Soft material and suitable size. easy to take out and use. Also IPX7 waterproof. you can use it when taking a shower. USB DC rechargeable. you can enjoy 45 mins after full charged.