Needle valves start, stop, and precisely throttle system media flow rates. Flow rates increase and decrease depending on the needle-shaped plunger's position relative to the seat within the housing. Flow increases as the valve's plunger is lifted away from the seat within the housing and flow decreases as the plunger is lowered closer to the seat. Instrumentation needle valves are compact and suit high-pressure applications such as process measurement. Precision metering instrumentation needle valves are similar to instrumentation needle valves but measure flow rates and have a finer stem for precise flow control in laboratory applications. High-purity needle valves are used in hygiene-sensitive applications, such as pharmaceutical manufacturing.