LS Enhancing Adjustable Vibrating Penis Rings

Adjustable diameter, one that wraps around the base of your penis, and one that's around your testicles. Great looking cock restraint that improves erections for most people. These simple rings will go a long way, and you'll be surprised how much it'll do for you with the vibration. 

How a cock ring can improve your sex quality? (healthline.com)

These sexual devices help trap blood in and around the penis to prevent it from flowing out during an erection.

This makes the penis tissue harder — and slightly bigger — for a longer period of time. It can also delay orgasm to result in a more intense climax.