Features Nelprof, with its advanced control-valve selection features, was first introduced in 1981. Now Nelprof 6 can be used to select all Metso�s automated onoff and emergency valves. Performance analysis, which has been one of the value-adding features in the control-valve sizing tool since 1980�s, can be used to study valve controllability in a closed control loop. The module also includes multi-phase flow sizing as well as noise and cavitation prediction analysis.