I gotten several of EdenFantasys Vibrating Rings over the last year or so. If it were not for the fact that I can get one free with every order, then I probably wouldn't have bought or tried one. The ring is a cock ring, worn by the man and made for both of your pleasure.
The ring is made to constrict blood flow to keep the blood in the shaft of the penis. This makes the erect penis harder and (slightly) larger. The constricted blood flow makes the penis more sensitive. It also helps delay and heighten orgasm.
Since the man's penis slightly more engorged (bigger), then it adds a little extra to your sensations as well (obviously). With the vibrating ring, every time he is all the way to the hilt, the mini vibrator attached to the ring will touch your clitoris, making it even more enjoyable.
The EF ring is $5.99 and is good for one time use. It has up to 30 minutes of vibration and has instruction on how to use the toy on the back of the foil packet. As you can see from the picture, the ring is clear and the mini vibrator inside the ring is a pinkish-purple. It is made of TPR silicone and is hypo-allergenic, latex free, and phthalates free. Fully stretched the ring is 4 inches in diameter and un-stretched it is 1/2 inch in diameter.
I like that the ring is made for one time usage. That means take off and throw away, no cleaning, no mess, no hassle. It is made of silicone so if you are using a lube, remember that you can only use water based. The ring is very stretchy so it can fit around your dude's junk and dildos of any size (if you want to use it on your own). The vibrations aren't super strong but they aren't completely weak either. For me (a power hog) the vibrations did not do much, but if you are more sensitive then it will probably work for you. The ring is actually pretty quiet too. Overall, this is not a bad toy if you are getting it for free, I'm not sure if I would pay $6 for a disposable toy though. That said, I (personally) would not buy it simply because my boyfriend is not a fan of rings.