This is a Grade King Leveling Scraper with an Aggression bar installed

The aggression bar is mostly used in road grading applications.

It is designed to "bust" up the large rocks before they get to the grade blade, which increases the life of the grader blade tremendously.

This also helps to eliminate extreme jarring caused by the grader blade crushing large rocks.

The operator can use a variety of different blades to get the results he is needing, including a stinger blade (shown). 

The aggression bar is simply bolted onto the Grade King, which makes it easy to remove.