a plurality of {HEAD ~ second gripping members} which are associated with {TAIL ~ the bottom portion} and protrude from the interior surface thereof 
a plurality of { HEAD ~ second gripping members } which are associated with { TAIL ~ the bottom portion } and protrude from the interior surface thereof
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH