The "Heavy Duty" version of this valve has a heavier diaphragm that helps prevent the "hooting" sound when the engine decelerates because of a weak or leaking diaphragm and the "Standard" version does not have the heavier diaphragm.
0 280 142 110 The "Heavy Duty" version of this valve has a heavier diaphragm that helps prevent the "hooting" sound when the engine decelerates because of a weak or leaking diaphragm and the "Standard" version does not have the heavier diaphragm.