The Hoke 3900 Series needle valves are compact instrumentation valves developed for accurate flow regulation and dependable shutoff in analytical and industrial process systems. These valves feature a precision-machined non-rotating stem design that minimizes seat wear and galling while providing smooth adjustment and repeatable control characteristics. The robust body construction and chemically resistant sealing materials ensure reliable operation in demanding gas and liquid applications. Available in a variety of connection styles and configurations, the series supports flexible integration into instrumentation panels and sampling systems. Operating pressures are rated up to 3000 psig (207 bar) depending on valve configuration and materials. Typical applications include gas sampling, analyzer systems, calibration equipment, laboratory instrumentation, and general process control service requiring stable and repeatable flow adjustment.