What does a swarr bar do? Rear suspension bar I have never seen...

It would be great if I could use it as a replacement for the panhard bar.. does it work with the panhard bar? does it replace a torque are too? If not, which is better or is there a noticeable diference? These are my main questions personally.
 
It really helps the axles from trying to wind forward as a result of a lot of HP on launches. It is something I consider standard on all drag cars, along with welding the axle tubes. I usually fab my own or I have used some other weld in kits for a 8.8 in a fox.
 
I have a swarr bar on my car. After I bent the housing really bad a few years ago I installed it. It has worked good ever since under some sever use. I've had my car 4 wheel aligned several times since then and it's still straight. Definitely a mandatory item if you're going to do hard launches at the track on slicks