BenQ ScreenBar Halo is a light bar that clamps onto the top of your monitor. It lights your desk without screen glare and adds a back light to soften the contrast between the screen and the wall behind it.

Key features:

Switch between a front light for the desk, a back light for ambience, or both together.
Adjust brightness, color temperature from 2700K to 6500K, favorites, and modes with the wireless controller.
Let the built-in ambient sensor dim the light automatically to 500 lux.
Light a 63 x 40 cm area at 500 lux, with an asymmetrical optical design that avoids reflections on the screen.
Mount it without a base using the counterweight clamp, which fits flat, ultra-wide curved, and dual monitors.
Work under flicker-free LEDs certified for no blue light hazard.

It's powered from any USB port that supplies at least 5V/1.5A, so it can run from your Mac or a USB charger. The clamp fits flat monitors 0.7 to 6 cm thick and curved monitors 1.6 to 3.8 cm thick, with a pad included for ultra-slim displays. It costs $139, down from a regular price of $189.