NEEWER&reg; 10x4.5 inch 1045R Counter Rotating Propeller Blade For Quadcopter MultiCoptor 2 Pair Diameter of Shaft: 6.0mm Propeller length:25.4cm Adjustable by hole adapter (2mm, 3mm, 4mm, 5mm, 6mm, 7.8mm) Thickness of center: 9mm Weight:14 gram/pair