This is the APC 8x4.5MR Multi Rotor Pusher Propeller. **Not for use with gasoline engines.** FEATURES: Specifically designed for multi-rotor applications Designed for electric powered aircraft with rear facing motors that "push" the airplane forward Bridges the gap between Thin Electric and Slow Flyer props Lighter that the APC Thin Electrics with a higher RPM capability than the Slow Flyers Lightweight moulded nylon construction, grey in colour INCLUDES: APC 8x4.5MR Multi Rotor Pusher Propeller SPECS: Length: 8" Pitch: 4.5" Maximum RPM: 105,000/prop diameter (inches)