A counterweight is included with your Porter Cable 7424. This is a replacement counterweight.
The counterweight fits on the eccentric housing, located just above the backing plate. This is the part that causes the plate to orbit. The semi-circular weight orbits with your backing plate to balance out any irregular motion and make the Porter Cable operate more smoothly. With the addition of a counterweight, your Porter Cable 7424 will work like a charm and render a perfectly uniform finish every time.
The counterweight is for use with a 6” backing plate only