"HAVING INTERLOCKING GROOVES ALONG THE ENTIRE WIDTH OF EACH PANEL;FLOATING NUT ASSEMBLIES ARE RIVETED ON BOTH ENDS OF THE PANEL THAT ALIGN WITH MATCHING HOLES IN THE SIDERAIL;FRONT AND REAR EDGES OF THE PANEL HAVE EIGHT HOLES WITH FLOATING NUTS,WHICH ARE USED TO CONNECT THE FOUR ROLLER PADS;THE MAIN PANEL HAD TWO TIEDOWN RINGS"