The Hamilton Beach 921999001 Cutter Assembly is the rotating cutting unit installed at the bottom of the blender container. During operation, the motor transfers rotation through the clutch and spindle to turn the cutter, allowing its blades to process ingredients inside the container. This assembly is supplied without the blade gasket, so the gasket arrangement should be checked sepa... https://partsfe.com/cutter-assy-for-hamilton-beach-part-921999001