Designed for larger 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 diameter13″ / 330mmPropeller pitch5″ / 127mmHubthickness5/8″ / 15.9mmShaft diameter1/4″ – 5/16″ / 6.35mm – 7.94mm *Propeller Weight1.55oz / 43.9gDirection of rotationNormal / TractorMaterialGlass Fiber R CompositeColorBlack