Lower pitch angle is recommended for stock motors; higher pitch angle is recommended for modified motors; lower pitch angle can also be used with modified motors if improved acceleration is desired Blade geometry designed specifically for high compression ratio jet-pump systems Exclusive hub-end water seal keeps the nasty stuff out of precious parts Improve acceleration and top end while eliminating performance holes 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. IMPELLER YS-DF 14/21