Specification  AS6917/4 Mod Sharpened, Balanced, Polished Stock prop:  Diameter: 69mm Pitch: 115mm Ratio: 1.7 After Mod:  Diameter: 67mm Pitch: 121mm Ratio: 1.8 Diameter reduced, back-cuts, 90 degree angle trailing edges,tongue removed from leading edges and The blades have been thinned and the leading edge re-shaped. This is a great prop for stock or mod engines and helps hulls keep the nose down; it is well suited for all type hull, especially a great prop for Mono and Cat Hull