There are many apparently similar units available on Amazon, but as far as I can tell from the photos, they are all the same device: An LED ring lamp made by Neewer Electronics. Disregard any nonsense about which camera the device is suitable for. If there's adaptor-ring that matches your lens size, and you have a flash mounting on your camera, this will work with it. So shop around and buy from a reputable and cheap supplier.
First impressions are good. The unit is well-packaged in economic but quality packaging. The instructions are in Chinese/English but to be honest you don't need them. The LED ring is powered by a coiled lead with a connector that fits into a unit that slots into the flash hotshoe on top of the camera. This unit holds two AA batteries within, or can have the supplied 3.3V adaptor connected. A switch on the battery compartment depowers the ring, or selects mains or battery power.
The LED ring itself slides onto one of six adaptor rings that screw onto the front of your lens. The rings are of acceptable quality and when, with care and a little trepidation, I screwed the adaptor onto the front of my Nikon lens, it screwed on smoothly. There is a switch on the LED ring that selects either left or right half of the ring to be illuminated or the full ring. The LED ring can be rotated on the adaptor ring to allow you to direct your "half" as you see fit. The rotation is a little loose but that could easily be remedied by most owners.
In use, the fact that it is a lamp and not a flash unit is a mixed blessing. One benefit is that for macro work, it allows easy focussing and provides what I would call a WYSIWYG facility that is not possible with flash, unless you take a test picture. The light is good, but like all unfocussed LED lights, the light intensity fades rapidly with distance, so don't expect to get strong light if used over one metre away. It works well when used within it's limitations.
THE DISADVANTAGE IS THAT IT IS THE PHOTOGRAPHIC EQUIVALENT OF UPPER CAPS TYPING. WHEN I APPROACHED MY WIFE TO PHOTOGRAPH HER, I GOT A PAINED, SQUINTING EXPRESSION WHICH IS "ONLY TO BE EXPECTED WHEN YOU'RE POINTING THAT RUDDY SEARCHLIGHT AT ME. NOW TURN IT OFF!!!" I would respectfully suggest that this is not a unit that would be ideal for portrait work, unless you're building a portfolio of squinting people.
Interestingly, I noticed that the battery unit had a tripod thread machined into the underside of the hotshoe plate. A minor, but thoughtful addition that may come in useful if you need to use your camera hotshoe for another device.
Overall, I am very pleasantly surprised by this device. I bought it as a cheap supplement to my existing flash, and for under £33 delivered, it satisfies that requirement but also manages to exceed my expectations by being better engineered and manufactured than could reasonably be expected for the price.
The Neewer LED Ring light is well worth having amongst your kit!