{HEAD ~ A casing} is mounted to two respective outer peripheries of {TAIL ~ the two end caps} and accommodates the axle therein 
{ HEAD ~ A casing } is mounted to two respective outer peripheries of { TAIL ~ the two end caps } and accommodates the axle therein
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH