LENO MSV-D is a new generation of manual valves for balancing flow in heating and cooling systems. Dynamic balancing valves are the preferred option for hydronic balancing in constant and variable flow systems. If manual balancing valves are used for hydronic balancing they are better suited for constant flow systems. Manual balancing valves can be used in both constant and variable flow systems for flow verification, shut off function for service and repair. The valve may be mounted in flow or return.