I bought this Ruyilam Ring Light as it was recommended to me along with a webcam.
It's very easy to use, and works right out of the box - no issues with USB2 or 3 ports at all.
There is plenty of cable, with a control panel in the centre, housing very intuitive user-friendly buttons.
There are three modes or 'colours' - a default brilliant light, a warm light and a normal enough light. Each mode can be adjusted up to ten times I think, so you can have it really low or really bright or somewhere in between.
I teach a lot online so it is a brilliant addition to any situation involving a webcam and online conferencing or whatever.
In the first photo above the light is clipped on to my laptop which is a fairly normal scenario. Next, there is a photo of how it clips on to the screen. The clip is not quite wide enough for a desktop computer screen and may spring off due to strain if it fits at all. I suppose it is designed more for laptops, although it does come with a very convenient tripod, so it doesn't always have to be fitted onto a screen.
In the other photos above, from left to right, there is a picture with no light, warm light, normal light and lastly the brilliant light. I'm sure it would be easy to get a little bit creative with positioning too.
I would highly recommend this device as it is reasonably priced and it is actually very helpful in providing a lighting solution that you may not have even realised was an issue. Very nice indeed.