3KEY USB Dimmer Switch Cable with 5V 2A Inline Controller, 8-Level Brightness Adjustment for LED Strip Lights, USB Desk Lamp, Re

Pretty cool. It seems to work by pwm or pulse width modulation. There isn't a voltage drop and i think i measured 2000 hz so the duration - going from memory so don't hold me to that - of the power will be reduced as you dim it. It works on most led loads that i have tried it on except a string of flashing leds which go from color to color and also flash in different patterns. This might be because of the chips and programs associated on the chips themselves. On that particular string, they only go to red, probably because they reset on every cycle. No biggie. I like the little dimmer switch. On off and up and down. I recommend it for it's expected use.

This is my second one to use with a non dimmable led display light system. it works well and there is no flickering of the led lights when dimmed. great controller.

Used with a USB fan in a van, allows you to adjust the speed. Perfect.

Works as advertised. i used it with a small led lamp as a keyboard light. nice to have some control over the intensity and brightness. also worked with a fan i have. the length is ok for my uses. a+ will buy another.