{HEAD ~ These ring compounds} are maintained in a concentration of {TAIL ~ between 0.01 and 4.0 grams} per liter of solution in the bath 
{ HEAD ~ These ring compounds } are maintained in a concentration of { TAIL ~ between 0.01 and 4.0 grams } per liter of solution in the bath
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH