Product review (5 stars): If your old one keeps flying off, this is the solution.
The one in our washing machine had the clipping points worn smooth - I don't know what the prior residents of this condo did to it to destroy it so completely, but most of the time during the spin cycle it would come off and we would need to risk bodily injury to turn the machine back off and put the agitator filter back on.  Hasn't happened once since replacing it with the new one, and we've done a lot of laundry since then.