These small valves are used to accurately regulate {HEAD ~ the flow} of {TAIL ~ fluids} and gases at certain flow rates 
These small valves are used to accurately regulate { HEAD ~ the flow } of { TAIL ~ fluids } and gases at certain flow rates
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH