In general, {HEAD ~ the protruding cylinders} have flat top surfaces, are preferably about 0.1 mm shorter than {TAIL ~ the thickness} of the welded unit, and have diameters that are preferably about 0.1 less than the diameters of the flexible membrane through holes 
In general , { HEAD ~ the protruding cylinders } have flat top surfaces , are preferably about 0.1 mm shorter than { TAIL ~ the thickness } of the welded unit , and have diameters that are preferably about 0.1 less than the diameters of the flexible membrane through holes
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH