This unique impeller enhances all-range maneuverability with no slippage in water hookup, Variable pitch offers both low-speed torque and all-out high speed in one impeller, Exclusive hub-end water seal keeps the nasty stuff out of precious parts, Constructed of ultra high-strength, corrosion-resistant stainless steel, Mirror-smooth finish and polished hub resists cavitation, Impeller pitch is determined by casting, not bending