I used mine last year to find 5 deer and 1 turkey. The blood hunter works very well with marginal blood trails. It will run about 1 1/2 hours with both lights on. One other thing I like about this light is if you have a good blood trail you can use the green light, the blood will look like glossy black paint. Which is good for color blind people. My hunting partner is color blind but he can see blood drops in green light. An excellent light to own. Before we used flashlights and tried different colored lenses. We did not find all the deer we looked for.
Last we had a light blood trail, a few drops every 10 to 15 feet for about 80 yards then every 30 feet or so until the guy holding the light stepped on his dead deer.
I am not saying you will find every animal but your chances are greater with this light.