APC Thin Electric 6x4 Prop
APC Thin-Electric Series props offer high efficiency and great value for your electric powered models. The center hole of the prop is designed to accept a reducing bushing to fit your propeller shaft. Included with the prop are 2 bushings to fit 5mm and 3/16 inch prop shafts.
According to the widely accepted Maximum RPM formula of 190,000/D for APC Speed 400 props, the 6x4E prop should not be used over 31,667 RPM.