Description: best delivery head at the point of optimum efficiency; Name: optimal head of the pump
Description: Total head developed by the pump at a rate of flow corresponding to the best efficiency; Name: Optimum head
Description: Speed that characterizes a pump in terms of its speed, flow rate per impeller eye, i.e. total flow for single-flow impeller, half flow for double-flow impeller, at the best efficiency point and head per stage at maximum impeller diameter ; Name: Specific speed