This is a Master Airscrew 10x8 Nylon Prop for Electric motors. FEATURES: Glass-filled nylon prop features rounded tips and thin airfoil. Lower noise and accurate balance. Available in a variety of sizes to suit different applications. Undercambered for more torque at lower RPM. INCLUDES: One 10x8 Nylon Propeller for Electric motors. SPECS: Center Hole Diameter: 3/16" approx. Propeller Diameter: 10" Propeller Pitch: 8" COMMENTS: These props are only for Electric motors and are typically used on 550 size motors. baw 01/02/02 ir/kh