{TAIL ~ The bellows} has undulations with ridges and valleys with {HEAD ~ ridge angles} determined such that contact between adjacent undulations when the boot is operatively connected is confined to a plane 
{ TAIL ~ The bellows } has undulations with ridges and valleys with { HEAD ~ ridge angles } determined such that contact between adjacent undulations when the boot is operatively connected is confined to a plane
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH