The Park DAG-2 is an updated version of the popular DAG-1. There are a multitude of ways in which a derailleur hanger can get bent out of alignment. A bent derailleur hanger can be the root cause of many problems like poor shifting, drivetrain noise, and difficult rear derailleur adjustment. The Park DAG-2 provides a perfect derailleur hanger alignment for exact shifting and a super-quiet drivetrain. This is a must-have tool for any serious mechanic. The new DAG-2 utilizes a longer measuring pointer, longer threaded stud and a longer, and has a narrower alignment boss to fit a wider variety of bikes.