This is a set of optional Carbon Tail Rotor Blades from Century Heli for the Hummingbird Pro 3D Heli. FEATURES: Carbon fiber construction, black in color Perfect spanwise and cordwise balance INCLUDES: Two Carbon Tail Blades for the Hummingbird Pro 3D Heli REQUIRES: Installing on tail rotor SPECS: Length: 2.1" (54mm) Width: 0.75" (19mm) Hole: 0.079" (2mm)