Brand new rubber blender coupler replaces KitchenAid, 9704230. The blender's rubber coupling is designed to break if the blender is under strain. This will often happen if the food being chopped is too hard or being chopped at too higher speed. The part failing prevents the motor from more severe damage.The coupler/clutch has six rubber teeth which grip the underside of the blade in the blending jug. The clutch is secured to the blender spindle (which is made of steel) with a reverse aluminum thread. i.e. you turn clockwise to undo it which is the opposite to normal.There are two ways to remove the old clutch. First you can use a thin 7mm spanner to grip the flats on the spindle under the coupler then turn the coupler clockwise. Second you can use a large flat bladed screwdriver to gently prise the coupler off the spindle. If you use the second method the aluminium thread in the coupler will be stripped as aluminum is softer. This is not a problem as the coupler will need replacing anyway. Make sure you clean off any pieces of aluminum left in the thread on the spindle.