Is a Hunter add on that has a focus bar, but It is much more than just a bigger focus bar. It is a focus bar with configurable ticks on it for your different shots. And you can configure then for your spec main shots. For the Beast Master spec you would want to set it up so one of your ticks are set for Kill Commend. There is a Misdirection module that tells who you cast it one, whispers the target that you are transferring threat to them. It will show a little window icon of what aspect you are in at the time and if you target a mob that you need to apply Hunters Mark. This mod is infinitely configurable for the hunter. There is also an Enrage module that will inform you when a mob is under an enrage effect that can be tranquilizing shot off. These are just a few of the ones I use the most. I could not imagine running my hunter with out Serenity as my add on of choice.