Whirlpool Genuine OEM 80040 Washer Agitator Directional Cogs Set. This set includes 4 per package. 
The agitator directional cogs ratchet across the gear teeth in one direction and dig into the gear teeth in the opposite direction to create the agitation.
This part works with the following brands: Whirlpool, Roper, Admiral, Maytag, Hardwick, Jenn-Air, Estate, Magic Chef, Crosley, Inglis, Norge, Modern Maid, Amana, Kenmore, KitchenAid, Caloric & Ikea.
This part is also known as washing machine agitator directional cogs, dog ears.