Three-way stainless steel manual instrumentation ball valves are abrasion-resistant, corrosion-resistant, compact, rated for high-pressure applications, and used in control and measurement systems. They stop media for collecting samples and installing flow-measuring devices and other instruments without the need to shut the system down. These valves have three ports that can act as inlets or outlets for mixing, splitting, or directing the flow of chemically compatible media, depending on the flow pattern (e.g., Y, T, or L). Manual-operated valves open and close with a handle and, depending on the handle's position, can visually indicate whether the valve is open or closed.