CNC 6014352 3 Blade Magnalium 7075 propeller. Hardened for strength. Machine-cut to high tolerances, this prop is ready to use right out of the box. The Magnalium 7075 alloy makes this material upwards of 30% stronger than standard 7075 aluminum. Left-hand rotation. These spin counterclockwise when viewed from the back of the boat. - Fits 3/16"(.187" 4.75mm) Smooth Bore Propeller Shafts.- Hard oxygen-anodized coating for added strength.