I bought one two weeks ago and it just so happens my dog cut her foot and I went out side at dark and her blood did show up really well. I tried it in the field to see what it would doon the red leaves on the ground and it made them "jump out" also. So I am gonna keep it, it will make the color red jump out on the ground. And the flash light is pretty powerful for a little light I use it when I coyote hunt.