The assembly is provided with ribs extending entirely around {HEAD ~ the bottom surface} of the seat for {TAIL ~ improved structural support} 
The assembly is provided with ribs extending entirely around { HEAD ~ the bottom surface } of the seat for { TAIL ~ improved structural support }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL