I don't know about the Primos light, but I can give you a first hand account on the Gerber Carnivor. DON'T buy it.Here is the first hand account. I shot a buck and had a great blood trail and found the deer within 100 yards. It got dark and I thought "Hey what a good chance to see if this light works" Going back over the trail with the " blood tracking light on, it did NOT make the blood show up any better. A good white light flashlight worked just as well.

Good luck hunting.