It's a spherical rod bearing to help the tie-rod end on lowered cars. You'll want to get the X2 balljoints first though, that will help the most.
Look underneath the front of your [lowered] car, youll notice how the outside end of your A arms angles upward, and notice the angle of the tie rods, how they are not in line with the steering rack itself. Stock, everything is perfectly lateral.
Stay away from offset rack bushings and the bumpsteer kit until you get the X2 balljoints or something equal (you're just looking for the longer stud).