In {TAIL ~ preferred embodiments}, {HEAD ~ the pitch} between corrugations may be five inches, with a depth of one half inch 
In
In { TAIL ~ preferred embodiments } , { HEAD ~ the pitch } between corrugations may be five inches , with a depth of one half inch
REL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH