{HEAD ~ The top units} may be preassembled with {TAIL ~ specific cooking system types} prior to mounting onto the base units 
preassembled with
{ HEAD ~ The top units } may be preassembled with { TAIL ~ specific cooking system types } prior to mounting onto the base units
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH