Item number: lb19909 x 3E 2 book and x 3EP 2 comes with two propeller 4 piece set 3 mm, 5 mm, 6 mm adapter rings 4 PCs Specification: Propeller Diameter: 5/(approx 12.7 cm) Propeller Pitch: (approx 10.9 cm) with hub diameter: 12.7 mm hub thickness: 7.1 mm shaft diameter: 6.3 mm Weight: 5.1 G