{HEAD ~ The retainer} is open sided, and has {TAIL ~ upper and lower walls} with notches for snapping into place in an aperture in a mounting channel in which the shelf bracket is mounted and in overlying relation to said bracket 
has
{ HEAD ~ The retainer } is open sided , and has { TAIL ~ upper and lower walls } with notches for snapping into place in an aperture in a mounting channel in which the shelf bracket is mounted and in overlying relation to said bracket
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH