A feature of {TAIL ~ the invention} relates to {HEAD ~ the material} used on the contacting surfaces of the base member and the flaps 
A feature of { TAIL ~ the invention } relates to { HEAD ~ the material } used on the contacting surfaces of the base member and the flaps
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH