said fourth plane of said edges of {HEAD ~ said open top side} of {TAIL ~ said clasp lower part} being parallel to said first plane of said upper surface of said clasp upper part  
of
said fourth plane of said edges of { HEAD ~ said open top side } of { TAIL ~ said clasp lower part } being parallel to said first plane of said upper surface of said clasp upper part
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD 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