MASTER AIRSCREW 16 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 16" / 406mm Propeller pitch 4" / 102mm Hub thickness 3/4" / 19.1mm Shaft diameter 5/16" - 3/8" / 7.94mm - 9.53mm * Propeller Weight 3.1oz / 87.9g Direction of rotation Normal / Tractor Material Glass Fiber R Composite Color Black