The Surefire Kroma is an interesting light, with white, red, and blue LEDs. The main LED is a bright white, with a ring of red and blue LEDs around it for secondary lighting. Below the head is a selector ring that you can turn to select between the different colors and intensities of each.
Since everyone always asks, I’ll give give you an idea of how the other colors are used. Red light is one of the least intense visible lights, so it is great for preserving night vision or using when you do not want to give away your position. Blue helps with blood tracking and fluid detection, since it will help the fluids contrast with other materials around them.
The Kroma is a pricey light with some pretty specific uses, but if you need its features, then you won’t find a better light.