The high-density foam grips allow you to really dig in and activate biceps. The position of the weight out in front of the bar helps to put more tension on the biceps than a standard curl. You're fighting not only the weight itself but the pull of the weights trying to rotate down.

 

The benefit of this tension and gripping requirement is more focused bicep activation, increasing the efficiency of your workout. It also puts a very different type of tension on the biceps - if your bicep training is stale, this bar will give it a good kick to get past a plateau.