When the device is subjected to the intake manifold vacuum, {HEAD ~ the upper half} of the elastic coating reacts by varying in {TAIL ~ size} to reflect the magnitude of the vacuum 
reacts by varying in
When the device is subjected to the intake manifold vacuum , { HEAD ~ the upper half } of the elastic coating reacts by varying in { TAIL ~ size } to reflect the magnitude of the vacuum
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL REL REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH