Mercury - Quicksilver Black Diamond Bravo Two Propeller 18.25" Diameter x 19" Pitch Left-Hand Rotation 3 Blades Aluminum Black Finish QA1941R. Overview. You can always tell when a prop is doing its job right - your boat feels steady, your throttle responds instantly, and the power comes on smooth without the vibration or strain. The Quicksilver Black Diamond Bravo Two Propeller gives you exactly that kind of confidence. Designed for the muscle and torque of Bravo Two drives, it's strong, balance