Mercury Racing Bravo Three XR Sterndrive drive performance enhancements, once limited to racers and performance boaters, are now available for recreational sport cruisers. The counter rotating, duel propeller Three XR is a natural behind the Axius – Joystick Piloting 520. Our line of precision-matched, high polished propellers feature a unique combination of a four-blade front propeller and a three-blade rear propeller for enhanced overall performance as well as propeller durability.