The retaining pawls are capable of being retained on {TAIL ~ the peripheral edges} of {HEAD ~ the retaining grooves} 
The retaining pawls are capable of being retained on { TAIL ~ the peripheral edges } of { HEAD ~ the retaining grooves }
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD