Lockshield Return Valves is for isolation and balancing. Some versions proposed drain off or setting memory. Easy setting with standard Allen Key or specific tool. This valve can be compared with a Globe Valve which can be used for isolating and balancing (with low accuracy), the difference between the Lockshield valve and globe valve is accessibility. Globe valve can be used by anybody who want to operate that, while access to the Lockshield valve is not possible for everybody unless by removing the cap by tools and adjusting or closing the valve by Allen key which only the maintenance people carry them.