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 diameter15″ / 381mmPropeller pitch10″ / 254mmHubthickness11/16″ / 17.5mmShaft diameter5/16″ – 3/8″ / 7.94mm – 9.53mm *Propeller Weight2.4oz / 68gDirection of rotationNormal / TractorMaterialGlass Fiber R CompositeColorBlack