Solas Rubex 40-40hp 3-Blade Aluminum Propeller utilizes a state-of-the-art squeeze-casting process which makes their aluminum propellers stronger and tougher than traditional die-cast props. Squeeze-casting produces propellers with finer grain and much less porosity than die-casting, for thinner yet stronger blades. This provides outstanding acceleration, cruising, and top speed. Use with compatible Rubex Hub Kit (not included). State-of-the-art squeeze-casting process Stronger and tougher than traditional die-cast props Finer grain and less porosity than die-casting Great acceleration, cruising, and top speed