10x4.5" Inch 1045 1045R Counter Rotating Propeller For MultiCoptor 2 Pairs 10x4.5 Propeller Size: 10*4.5'' Diameter of Shaft: 6.0mm Adjustable by hole adapter (3mm, 3.2mm, 4mm, 5mm, 6mm, 6.35mm, 7.95mm) Thickness of center: 9.7mm Recommended wheelbase: 550mm - 700mm