This is an APC Propellers 9 x 4.5 Multi-Rotor Propeller. APC is proud to provide a line of propellers specifically designed for Multi-Rotor applications (Quad-Copters). These propellers bridge the gap between our Thin Electric propellers and Slow Flyer propellers. The ‘MR’ propellers are lighter than the Thin Electrics and have a higher RPM capability than the Slow Flyers.
Number of Blades: 2 Blade
Propeller Size: 9 x 4.5
Maximum RPM: 105,000/prop diameter (inches)