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