The disclosed fluid elements include radial blades extending to trailing edges and that are integral with front and rear shrouds to provide a fluid exit. Fillets adjoin the trailing edge and the front and rear shrouds at the exit. The front and rear shrouds respectively have first and second perimeter thicknesses at the impeller outer perimeter. The first perimeter thickness is greater than the second perimeter thickness at the trailing edge and adjacent to the exit, which provides greater high cycle fatigue in the area of the fillets.