MASTER AIRSCREW 15 X 4 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 14" / 356mm Propeller pitch 6" / 152mm Hub thickness 5/8" / 15.9mm Shaft diameter 1/4" - 5/16" / 6.35mm - 7.94mm * Propeller Weight 2.05oz / 58.1g Direction of rotation Normal / Tractor Material Glass Fiber R Composite Color Black