Needle Valve 3 : A valve used on small, high-pressure piping where accurate control of small amounts of liquid or gas is desired. Also used with pressure gages. (ITOGP).
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}