Product review (5 stars): Exactly what I needed.
Having several years experience repairing appliances, I already knew what I needed. That being said, this part repairs the following issue: On most Whirlpool top-load washing machines, these little plastic pieces keep the agitator spinning one direction, which causes the screw on the agitator to force the laundry toward the bottom of the basket. If these little cams are stripped, your laundry is not getting as clean, plain and simple.

The method to test for this is to, while the machine is off, grab the agitator and try to spin it both directions. If it spins freely in both directions, you need new cams.