{HEAD ~ The blister} when in its piercing position is interposed between the delivery channel and {TAIL ~ the connection channel}  
is interposed between
{ HEAD ~ The blister } when in its piercing position is interposed between the delivery channel and { TAIL ~ the connection channel }
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH REL REL REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH