Agree with Biggie. I bought one of the Primos lights when they first came out and it just doesn't work as advertised. I can see blood better with a flashlight than with that thing. I keep it in my recovery pack along with that spray stuff that supposedly helps the blood glow when hit with a flashlight, but I don't use either one because they don't work for me. Now don't laugh, but I did buy one of those Game Finder thermal imaging units. I wouldn't have even considered one, but had a guy in hunt camp last year use one to find my big 10 point in Missouri that left virtually no blood trail 4 hours after the shot. Now, the thing only went 80 yards and I would have found him anyway, but I was impressed with how well it worked.