The position of the tray is then secured with {HEAD ~ a fastener} screwably extending through {TAIL ~ the second arm} into a friction fit relationship with the shelf 
screwably extending through
The position of the tray is then secured with { HEAD ~ a fastener } screwably extending through { TAIL ~ the second arm } into a friction fit relationship with the shelf
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH