This blade drive assembly lever is the part that moves the blade back and forth enabling the cutter to cut hair efficiently.
It should be replaced when blades are no longer cutting efficiently.
Andis Blade Drive for the following clippers;
AGC, AG, AGP, Excel (SMC), AGCl, PWRGRM, AGR, AGRC, BGRC
Measures 3-1/2-inch length by 2-1/2-inch width by 1/2-inch height.