ophoria
The Ophoria V-Ring (V is for vibrating), provided by Babeland, is my first cock ring to review. Wahoo! This ring is velvety-soft, 100% silicone, and stretchy.  Plus it vibrates. ^__^
Something new I learned is that it should not be worn for more than 30 minutes in one go. Seems reasonable.
So my boyfriend and I set about reviewing this ring. It was stretchy enough to go on when the penis was semi-erect. There is no possible way this ring could stretch over the shaft and the balls in our case. The vibration felt faint and did not add much to the experience. What he and I did really enjoy was that this ring kept his penis firmer than normal. This was very noticeable in the tip of the penis, as it was harder than what is typical, and this felt great during sex. However, this might be typical of most cock rings.
We also like that this product is made of silicone, because it can stretch as much as we need it to. We would not prefer to use any ring that is made of less pliable materials, such as metal.

The product details for the Ophoria V-Ring are as follows:

Size: 1.5″
Stretch: up to 5.5″
Material: Silicone
Power: 2 Micron Button batteries (last for 40 minutes)
It was difficult stretching it to approximately 4 inches. While my boyfriend and I had a positive experience with this cock ring, I am sure there are other rings we would be more and less pleased with. We were not impressed with the low vibration intensity of this ring. We were pleased with the stretch factor and the fact that it fit the way it should. When shopping for a cock ring, make sure it is not too loose or tight for you. This should be relatively easy as it seems there is a general range of ring sizes for folks. In addition, vibrations are not for everyone, but many people enjoy the sensation. Be a smart shopper and choose what meets your criteria.
Thank you Babeland for allowing me to review the Ophoria V-Ring!  For other vibrating cock rings, check out Babeland here.