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