Each of {HEAD ~ the inside surfaces} of the two external washers comprise {TAIL ~ an actuation plane} corresponding to one of the associated lateral retaining elements 
Each of { HEAD ~ the inside surfaces } of the two external washers comprise { TAIL ~ an actuation plane } corresponding to one of the associated lateral retaining elements
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH