The metal cover may provide a plurality of legs and fins each coming in {HEAD ~ contact} with and pushing {TAIL ~ the walls} of the groove 
The metal cover may provide a plurality of legs and fins each coming in { HEAD ~ contact } with and pushing { TAIL ~ the walls } of the groove
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH