{HEAD ~ A compressing means} is preferable over {TAIL ~ even simpler direct compression} of the compressible portion 20 by a user, as the compressing means may be adapted to provide a predetermined pressure force which is sufficient for closing the transfer path 35 from the outside 
is preferable over
{ HEAD ~ A compressing means } is preferable over { TAIL ~ even simpler direct compression } of the compressible portion 20 by a user , as the compressing means may be adapted to provide a predetermined pressure force which is sufficient for closing the transfer path 35 from the outside
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH