I've been using NAP Killzones for around 7 years. Started using them when I bought my Ten Point Titan Xtreme and continue with my Viper S400. Harvested two deer this year with them, the buck fell in his tracks and the doe went 50 yards and crashed. I've had good success with them, and continue to use them. The only negative for me is that the early ones that I purchased were made in the USA, and they have since sent them over seas.