MASTER AIRSCREW 12 X 8 PROP K SERIESPerformance Propellers for Model Airplanes - K Series Designed for larger 2 and 4 stroke glow engines and electric conversion models. The K series provides great performance and durability. Made of Glass Fiber Reinforced Composite in sizes 12 to 16". Propeller diameter 12" / 305mm Propeller pitch 8" / 203mm Hub thickness 9/16" / 14.3mm Shaft diameter 1/4" - 5/16" / 6.35mm - 7.94mm * Propeller Weight 1.27oz / 36g Direction of rotation Normal / Tractor Material Glass Fiber R Composite Color Black