The red light is suppose to go un-detected by deer because their eyes won't pickup that color as well as a bright white light.I use my red light in the early mornings when I slip into my stands before the sun comes up....kinda hard to see by it but you just don't move as fast!I believe the green light is also hard for the deer to see but easy for us to see at night...and the green colored light shows up blood better when trailing in the late evening or after dark.