Ball valves control the flow of water. When the valve is closed, the hole is perpendicular to the ends of the valve, and flow is blocked. The handle or lever will be in-line with the port position letting you "see" the valve's position. Ball valves are typically very durable and usually work excellent for shut-off applications. It is important to consider pressure, temperature and any type of solvent that you plan to run through these units. If you have questions or concerns, don't hesitate to give us a call so we can help you select the right ball valve for your application.