The base 12 defines {TAIL ~ four fastener holes} 19 in {HEAD ~ the bottom surface} 18 thereof engaging the posts 20 
The base 12 defines { TAIL ~ four fastener holes } 19 in { HEAD ~ the bottom surface } 18 thereof engaging the posts 20
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH