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