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 5 bushings to fit 3mm, 4mm, 5mm, 6mm and 8mm prop shafts.
According to the widely accepted Maximum RPM formula of 190,000/D for APC E-Series props, the 9x4.5E prop should not be used over 21,111 RPM.
Hub Diameter: 0.80 in. Hub Thickness: 0.39 in. Shaft Diameter: 1/4 in. Product Weight: 0.63 oz.