Ball valve locking kits are security devices that allow you to secure a ball valve in order to prevent it being operated, unintentionally or without authorisation. They essentially provide a space for a padlock to be inserted, though the padlock does not generally come included in the kit.
Ball valves are a type of control device that use a hollow, perforated ball to affect flow passing through it. When the holes in the ball are in line with the flow, the valve is open, and it can be closed by turning the handle a quarter-turn. Ball valve locking kits prevent the handle from being turned, so it will remain either open or closed depending on its function in the hydraulic system.
All ball valve locking kits function in broadly the same way, but they can be made from different materials depending on the environment, system or process to which they will be attached.