The first sidewall and {TAIL ~ the protective wall} cooperate to define a clevis structure including {HEAD ~ a channel} 
The first sidewall and { TAIL ~ the protective wall } cooperate to define a clevis structure including { HEAD ~ a channel }
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD